summary refs log tree commit diff
path: root/docs/usage/configuration/config_documentation.md
blob: 3ad3085bfac12e7efc0e0b46efc4dc7164323006 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
# Configuring Synapse

This is intended as a guide to the Synapse configuration. The behavior of a Synapse instance can be modified 
through the many configuration settings documented here — each config option is explained, 
including what the default is, how to change the default and what sort of behaviour the setting governs.
Also included is an example configuration for each setting. If you don't want to spend a lot of time 
thinking about options, the config as generated sets sensible defaults for all values. Do note however that the
database defaults to SQLite, which is not recommended for production usage. You can read more on this subject 
[here](../../setup/installation.md#using-postgresql).

## Config Conventions

Configuration options that take a time period can be set using a number
followed by a letter. Letters have the following meanings:

* `s` = second
* `m` = minute
* `h` = hour
* `d` = day
* `w` = week
* `y` = year

For example, setting `redaction_retention_period: 5m` would remove redacted
messages from the database after 5 minutes, rather than 5 months.

### YAML 
The configuration file is a [YAML](https://yaml.org/) file, which means that certain syntax rules
apply if you want your config file to be read properly. A few helpful things to know:
* `#` before any option in the config will comment out that setting and either a default (if available) will 
   be applied or Synapse will ignore the setting. Thus, in example #1 below, the setting will be read and
   applied, but in example #2 the setting will not be read and a default will be applied.  

   Example #1:
   ```yaml
   pid_file: DATADIR/homeserver.pid
   ```
   Example #2:
   ```yaml
   #pid_file: DATADIR/homeserver.pid
   ```
* Indentation matters! The indentation before a setting
  will determine whether a given setting is read as part of another
  setting, or considered on its own. Thus, in example #1, the `enabled` setting
  is read as a sub-option of the `presence` setting, and will be properly applied.
  
  However, the lack of indentation before the `enabled` setting in example #2 means
  that when reading the config, Synapse will consider both `presence` and `enabled` as
  different settings. In this case, `presence` has no value, and thus a default applied, and `enabled`
  is an option that Synapse doesn't recognize and thus ignores.
  
  Example #1: 
  ```yaml
  presence:
    enabled: false
  ```
  Example #2:
  ```yaml
  presence:
  enabled: false
  ```
  In this manual, all top-level settings (ones with no indentation) are identified 
  at the beginning of their section (i.e. "Config option: `example_setting`") and 
  the sub-options, if any, are identified and listed in the body of the section. 
  In addition, each setting has an example of its usage, with the proper indentation
  shown. 

## Contents
[Modules](#modules)

[Server](#server)

[Homeserver Blocking](#homeserver-blocking)

[TLS](#tls)

[Federation](#federation)

[Caching](#caching)

[Database](#database)

[Logging](#logging)

[Ratelimiting](#ratelimiting)

[Media Store](#media-store)

[Captcha](#captcha)

[TURN](#turn)

[Registration](#registration)

[API Configuration](#api-configuration)

[Signing Keys](#signing-keys)

[Single Sign On Integration](#single-sign-on-integration)

[Push](#push)

[Rooms](#rooms)

[Opentracing](#opentracing)

[Workers](#workers)

[Background Updates](#background-updates)

## Modules

Server admins can expand Synapse's functionality with external modules.

See [here](../../modules/index.md) for more
documentation on how to configure or create custom modules for Synapse.


---
Config option: `modules`

Use the `module` sub-option to add modules under this option to extend functionality. 
The `module` setting then has a sub-option, `config`, which can be used to define some configuration
for the `module`.

Defaults to none.

Example configuration:
```yaml
modules:
  - module: my_super_module.MySuperClass
    config:
      do_thing: true
  - module: my_other_super_module.SomeClass
    config: {}
```
---
## Server ##

Define your homeserver name and other base options.

---
Config option: `server_name`

This sets the public-facing domain of the server.

The `server_name` name will appear at the end of usernames and room addresses
created on your server. For example if the `server_name` was example.com,
usernames on your server would be in the format `@user:example.com`

In most cases you should avoid using a matrix specific subdomain such as
matrix.example.com or synapse.example.com as the `server_name` for the same
reasons you wouldn't use user@email.example.com as your email address.
See [here](../../delegate.md)
for information on how to host Synapse on a subdomain while preserving
a clean `server_name`.

The `server_name` cannot be changed later so it is important to
configure this correctly before you start Synapse. It should be all
lowercase and may contain an explicit port.

There is no default for this option. 
 
Example configuration #1:
```yaml
server_name: matrix.org 
```
Example configuration #2:
```yaml
server_name: localhost:8080
```
---
Config option: `pid_file`

When running Synapse as a daemon, the file to store the pid in. Defaults to none.

Example configuration:
```yaml
pid_file: DATADIR/homeserver.pid
```
---
Config option: `web_client_location`

The absolute URL to the web client which `/` will redirect to. Defaults to none. 

Example configuration:
```yaml
web_client_location: https://riot.example.com/
```
---
Config option: `public_baseurl`

The public-facing base URL that clients use to access this Homeserver (not
including _matrix/...). This is the same URL a user might enter into the
'Custom Homeserver URL' field on their client. If you use Synapse with a
reverse proxy, this should be the URL to reach Synapse via the proxy.
Otherwise, it should be the URL to reach Synapse's client HTTP listener (see
'listeners' below).

Defaults to `https://<server_name>/`.

Example configuration:
```yaml
public_baseurl: https://example.com/
```
---
Config option: `serve_server_wellknown`

By default, other servers will try to reach our server on port 8448, which can
be inconvenient in some environments.

Provided `https://<server_name>/` on port 443 is routed to Synapse, this
option configures Synapse to serve a file at `https://<server_name>/.well-known/matrix/server`. 
This will tell other servers to send traffic to port 443 instead.

This option currently defaults to false.

See https://matrix-org.github.io/synapse/latest/delegate.html for more
information.

Example configuration:
```yaml
serve_server_wellknown: true
```
---
Config option: `soft_file_limit`
 
Set the soft limit on the number of file descriptors synapse can use.
Zero is used to indicate synapse should set the soft limit to the hard limit.
Defaults to 0. 

Example configuration:
```yaml
soft_file_limit: 3
```
---
Config option: `presence`

Presence tracking allows users to see the state (e.g online/offline)
of other local and remote users. Set the `enabled` sub-option to false to  
disable presence tracking on this homeserver. Defaults to true. 
This option replaces the previous top-level 'use_presence' option.

Example configuration:
```yaml
presence:
  enabled: false
```
---
Config option: `require_auth_for_profile_requests`

Whether to require authentication to retrieve profile data (avatars, display names) of other 
users through the client API. Defaults to false. Note that profile data is also available 
via the federation API, unless `allow_profile_lookup_over_federation` is set to false.

Example configuration:
```yaml
require_auth_for_profile_requests: true
```
---
Config option: `limit_profile_requests_to_users_who_share_rooms`

Use this option to require a user to share a room with another user in order
to retrieve their profile information. Only checked on Client-Server 
requests. Profile requests from other servers should be checked by the
requesting server. Defaults to false.

Example configuration: 
```yaml
limit_profile_requests_to_users_who_share_rooms: true
```
---
Config option: `include_profile_data_on_invite`

Use this option to prevent a user's profile data from being retrieved and
displayed in a room until they have joined it. By default, a user's
profile data is included in an invite event, regardless of the values
of the above two settings, and whether or not the users share a server.
Defaults to true.

Example configuration:
```yaml
include_profile_data_on_invite: false
```
---
Config option: `allow_public_rooms_without_auth`

If set to true, removes the need for authentication to access the server's
public rooms directory through the client API, meaning that anyone can
query the room directory. Defaults to false.

Example configuration:
```yaml
allow_public_rooms_without_auth: true
```
---
Config option: `allow_public_rooms_without_auth`

If set to true, allows any other homeserver to fetch the server's public
rooms directory via federation. Defaults to false.

Example configuration:
```yaml
allow_public_rooms_over_federation: true
```
---
Config option: `default_room_version`

The default room version for newly created rooms on this server.

Known room versions are listed [here](https://spec.matrix.org/latest/rooms/#complete-list-of-room-versions)

For example, for room version 1, `default_room_version` should be set
to "1". 

Currently defaults to "9".

Example configuration:
```yaml
default_room_version: "8"
```
---
Config option: `gc_thresholds`

The garbage collection threshold parameters to pass to `gc.set_threshold`, if defined.
Defaults to none. 

Example configuration:
```yaml
gc_thresholds: [700, 10, 10]
```
---
Config option: `gc_min_interval`

The minimum time in seconds between each GC for a generation, regardless of
the GC thresholds. This ensures that we don't do GC too frequently. A value of `[1s, 10s, 30s]` 
indicates that a second must pass between consecutive generation 0 GCs, etc.

Defaults to `[1s, 10s, 30s]`.

Example configuration:
```yaml
gc_min_interval: [0.5s, 30s, 1m]
```
---
Config option: `filter_timeline_limit`

Set the limit on the returned events in the timeline in the get
and sync operations. Defaults to 100. A value of -1 means no upper limit.


Example configuration:
```yaml
filter_timeline_limit: 5000
```
---
Config option: `block_non_admin_invites`

Whether room invites to users on this server should be blocked
(except those sent by local server admins). Defaults to false.

Example configuration:
```yaml
block_non_admin_invites: true
```
---
Config option: `enable_search`

If set to false, new messages will not be indexed for searching and users
will receive errors when searching for messages. Defaults to true.

Example configuration:
```yaml
enable_search: false
```
---
Config option: `ip_range_blacklist`
 
This option prevents outgoing requests from being sent to the specified blacklisted IP address
CIDR ranges. If this option is not specified then it defaults to private IP
address ranges (see the example below).

The blacklist applies to the outbound requests for federation, identity servers,
push servers, and for checking key validity for third-party invite events.

(0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
listed here, since they correspond to unroutable addresses.)

This option replaces `federation_ip_range_blacklist` in Synapse v1.25.0.

Note: The value is ignored when an HTTP proxy is in use.

Example configuration:
```yaml
ip_range_blacklist:
  - '127.0.0.0/8'
  - '10.0.0.0/8'
  - '172.16.0.0/12'
  - '192.168.0.0/16'
  - '100.64.0.0/10'
  - '192.0.0.0/24'
  - '169.254.0.0/16'
  - '192.88.99.0/24'
  - '198.18.0.0/15'
  - '192.0.2.0/24'
  - '198.51.100.0/24'
  - '203.0.113.0/24'
  - '224.0.0.0/4'
  - '::1/128'
  - 'fe80::/10'
  - 'fc00::/7'
  - '2001:db8::/32'
  - 'ff00::/8'
  - 'fec0::/10'
```
---
Config option: `ip_range_whitelist`

List of IP address CIDR ranges that should be allowed for federation,
identity servers, push servers, and for checking key validity for
third-party invite events. This is useful for specifying exceptions to
wide-ranging blacklisted target IP ranges - e.g. for communication with
a push server only visible in your network.

This whitelist overrides `ip_range_blacklist` and defaults to an empty
list.

Example configuration:
```yaml
ip_range_whitelist:
   - '192.168.1.1'
```
---
Config option: `listeners`

List of ports that Synapse should listen on, their purpose and their
configuration.

Sub-options for each listener include:

* `port`: the TCP port to bind to. 

* `bind_addresses`: a list of local addresses to listen on. The default is
       'all local interfaces'.

* `type`: the type of listener. Normally `http`, but other valid options are:
    
   * `manhole`: (see the docs [here](../../manhole.md)),

   * `metrics`: (see the docs [here](../../metrics-howto.md)),

   * `replication`: (see the docs [here](../../workers.md)).

* `tls`: set to true to enable TLS for this listener. Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.

* `x_forwarded`: Only valid for an 'http' listener. Set to true to use the X-Forwarded-For header as the client IP. Useful when Synapse is
   behind a reverse-proxy.

* `resources`: Only valid for an 'http' listener. A list of resources to host
   on this port. Sub-options for each resource are:

   * `names`: a list of names of HTTP resources. See below for a list of valid resource names.

   * `compress`: set to true to enable HTTP compression for this resource.

* `additional_resources`: Only valid for an 'http' listener. A map of
   additional endpoints which should be loaded via dynamic modules.

Valid resource names are:

* `client`: the client-server API (/_matrix/client), and the synapse admin API (/_synapse/admin). Also implies `media` and `static`.

* `consent`: user consent forms (/_matrix/consent). See [here](../../consent_tracking.md) for more.

* `federation`: the server-server API (/_matrix/federation). Also implies `media`, `keys`, `openid`

* `keys`: the key discovery API (/_matrix/key).

* `media`: the media API (/_matrix/media).

* `metrics`: the metrics interface. See [here](../../metrics-howto.md).

* `openid`: OpenID authentication. See [here](../../openid.md).

* `replication`: the HTTP replication API (/_synapse/replication). See [here](../../workers.md).

* `static`: static resources under synapse/static (/_matrix/static). (Mostly useful for 'fallback authentication'.)

Example configuration #1:
```yaml
listeners:
  # TLS-enabled listener: for when matrix traffic is sent directly to synapse.
  #
  # (Note that you will also need to give Synapse a TLS key and certificate: see the TLS section
  # below.)
  #
  - port: 8448
    type: http
    tls: true
    resources:
      - names: [client, federation]
```
Example configuration #2:
```yaml
listeners:
  # Unsecure HTTP listener: for when matrix traffic passes through a reverse proxy
  # that unwraps TLS.
  #
  # If you plan to use a reverse proxy, please see
  # https://matrix-org.github.io/synapse/latest/reverse_proxy.html.
  #
  - port: 8008
    tls: false
    type: http
    x_forwarded: true
    bind_addresses: ['::1', '127.0.0.1']

    resources:
      - names: [client, federation]
        compress: false

    # example additional_resources:
    additional_resources:
      "/_matrix/my/custom/endpoint":
        module: my_module.CustomRequestHandler
        config: {}

  # Turn on the twisted ssh manhole service on localhost on the given
  # port.
  - port: 9000
    bind_addresses: ['::1', '127.0.0.1']
    type: manhole
```
---
Config option: `manhole_settings`

Connection settings for the manhole. You can find more information
on the manhole [here](../../manhole.md). Manhole sub-options include:
* `username` : the username for the manhole. This defaults to 'matrix'.
* `password`: The password for the manhole. This defaults to 'rabbithole'.
* `ssh_priv_key_path` and `ssh_pub_key_path`: The private and public SSH key pair used to encrypt the manhole traffic.
  If these are left unset, then hardcoded and non-secret keys are used,
  which could allow traffic to be intercepted if sent over a public network.

Example configuration:
```yaml
manhole_settings:
  username: manhole
  password: mypassword
  ssh_priv_key_path: CONFDIR/id_rsa
  ssh_pub_key_path: CONFDIR/id_rsa.pub
```
---
Config option: `dummy_events_threshold`

Forward extremities can build up in a room due to networking delays between
homeservers. Once this happens in a large room, calculation of the state of
that room can become quite expensive. To mitigate this, once the number of
forward extremities reaches a given threshold, Synapse will send an
`org.matrix.dummy_event` event, which will reduce the forward extremities
in the room.

This setting defines the threshold (i.e. number of forward extremities in the room) at which dummy events are sent. 
The default value is 10.

Example configuration:
```yaml
dummy_events_threshold: 5
```
---
## Homeserver blocking ##
Useful options for Synapse admins.

---

Config option: `admin_contact`

How to reach the server admin, used in `ResourceLimitError`. Defaults to none. 

Example configuration:
```yaml
admin_contact: 'mailto:admin@server.com'
```
---
Config option: `hs_disabled` and `hs_disabled_message`

Blocks users from connecting to the homeserver and provides a human-readable reason
why the connection was blocked. Defaults to false. 

Example configuration:
```yaml
hs_disabled: true
hs_disabled_message: 'Reason for why the HS is blocked'
```
---
Config option: `limit_usage_by_mau`

This option disables/enables monthly active user blocking. Used in cases where the admin or 
server owner wants to limit to the number of monthly active users. When enabled and a limit is 
reached the server returns a `ResourceLimitError` with error type `Codes.RESOURCE_LIMIT_EXCEEDED`.
Defaults to false. If this is enabled, a value for `max_mau_value` must also be set.

Example configuration:
```yaml
limit_usage_by_mau: true 
```
---
Config option: `max_mau_value`

This option sets the hard limit of monthly active users above which the server will start 
blocking user actions if `limit_usage_by_mau` is enabled. Defaults to 0.  

Example configuration:
```yaml
max_mau_value: 50
```
---
Config option: `mau_trial_days`

The option `mau_trial_days` is a means to add a grace period for active users. It
means that users must be active for the specified number of days before they
can be considered active and guards against the case where lots of users
sign up in a short space of time never to return after their initial
session. Defaults to 0. 

Example configuration:
```yaml
mau_trial_days: 5
```
---
Config option: `mau_appservice_trial_days`

The option `mau_appservice_trial_days` is similar to `mau_trial_days`, but applies a different
trial number if the user was registered by an appservice. A value
of 0 means no trial days are applied. Appservices not listed in this dictionary
use the value of `mau_trial_days` instead.

Example configuration:
```yaml
mau_appservice_trial_days: 
  my_appservice_id: 3
  another_appservice_id: 6
```
---
Config option: `mau_limit_alerting`

The option `mau_limit_alerting` is a means of limiting client-side alerting
should the mau limit be reached. This is useful for small instances
where the admin has 5 mau seats (say) for 5 specific people and no
interest increasing the mau limit further. Defaults to true, which
means that alerting is enabled.

Example configuration:
```yaml
mau_limit_alerting: false
```
---
Config option: `mau_stats_only`

If enabled, the metrics for the number of monthly active users will
be populated, however no one will be limited based on these numbers. If `limit_usage_by_mau`
is true, this is implied to be true. Defaults to false. 

Example configuration:
```yaml
mau_stats_only: true
```
---
Config option: `mau_limit_reserved_threepids`

Sometimes the server admin will want to ensure certain accounts are
never blocked by mau checking. These accounts are specified by this option.
Defaults to none. Add accounts by specifying the `medium` and `address` of the
reserved threepid (3rd party identifier).

Example configuration:
```yaml
mau_limit_reserved_threepids:
  - medium: 'email'
    address: 'reserved_user@example.com'
```
---
Config option: `server_context`

This option is used by phonehome stats to group together related servers.
Defaults to none. 

Example configuration:
```yaml
server_context: context
```
---
Config option: `limit_remote_rooms`

When this option is enabled, the room "complexity" will be checked before a user
joins a new remote room. If it is above the complexity limit, the server will
disallow joining, or will instantly leave. This is useful for homeservers that are
resource-constrained. Options for this setting include:
* `enabled`: whether this check is enabled. Defaults to false.
* `complexity`: the limit above which rooms cannot be joined. The default is 1.0.
* `complexity_error`: override the error which is returned when the room is too complex with a
   custom message. 
* `admins_can_join`: allow server admins to join complex rooms. Default is false.

Room complexity is an arbitrary measure based on factors such as the number of
users in the room. 

Example configuration:
```yaml
limit_remote_rooms:
  enabled: true
  complexity: 0.5
  complexity_error: "I can't let you do that, Dave."
  admins_can_join: true
```
---
Config option: `require_membership_for_aliases`

Whether to require a user to be in the room to add an alias to it.
Defaults to true.

Example configuration:
```yaml
require_membership_for_aliases: false
```
---
Config option: `allow_per_room_profiles`

Whether to allow per-room membership profiles through the sending of membership
events with profile information that differs from the target's global profile.
Defaults to true.

Example configuration:
```yaml
allow_per_room_profiles: false
```
---
Config option: `max_avatar_size`

The largest permissible file size in bytes for a user avatar. Defaults to no restriction.
Use M for MB and K for KB. 

Note that user avatar changes will not work if this is set without using Synapse's media repository.

Example configuration:
```yaml
max_avatar_size: 10M
```
---
Config option: `allowed_avatar_mimetypes`

The MIME types allowed for user avatars. Defaults to no restriction.

Note that user avatar changes will not work if this is set without
using Synapse's media repository.

Example configuration:
```yaml
allowed_avatar_mimetypes: ["image/png", "image/jpeg", "image/gif"]
```
---
Config option: `redaction_retention_period`

How long to keep redacted events in unredacted form in the database. After
this period redacted events get replaced with their redacted form in the DB.

Defaults to `7d`. Set to `null` to disable.

Example configuration:
```yaml
redaction_retention_period: 28d
```
---
Config option: `user_ips_max_age` 

How long to track users' last seen time and IPs in the database.

Defaults to `28d`. Set to `null` to disable clearing out of old rows.

Example configuration:
```yaml
user_ips_max_age: 14d
```
---
Config option: `request_token_inhibit_3pid_errors`

Inhibits the `/requestToken` endpoints from returning an error that might leak
information about whether an e-mail address is in use or not on this
homeserver. Defaults to false. 
Note that for some endpoints the error situation is the e-mail already being
used, and for others the error is entering the e-mail being unused.
If this option is enabled, instead of returning an error, these endpoints will
act as if no error happened and return a fake session ID ('sid') to clients.

Example configuration:
```yaml
request_token_inhibit_3pid_errors: true
```
---
Config option: `next_link_domain_whitelist`

A list of domains that the domain portion of `next_link` parameters
must match.

This parameter is optionally provided by clients while requesting
validation of an email or phone number, and maps to a link that
users will be automatically redirected to after validation
succeeds. Clients can make use this parameter to aid the validation
process.

The whitelist is applied whether the homeserver or an identity server is handling validation.

The default value is no whitelist functionality; all domains are
allowed. Setting this value to an empty list will instead disallow
all domains.

Example configuration:
```yaml
next_link_domain_whitelist: ["matrix.org"]
```
---
Config option: `templates` and `custom_template_directory`

These options define templates to use when generating email or HTML page contents.
The `custom_template_directory` determines which directory Synapse will try to 
find template files in to use to generate email or HTML page contents.
If not set, or a file is not found within the template directory, a default 
template from within the Synapse package will be used.

See [here](../../templates.md) for more
information about using custom templates.

Example configuration:
```yaml
templates:
  custom_template_directory: /path/to/custom/templates/
```
---
Config option: `retention`

This option and the associated options determine message retention policy at the
server level.

Room admins and mods can define a retention period for their rooms using the
`m.room.retention` state event, and server admins can cap this period by setting
the `allowed_lifetime_min` and `allowed_lifetime_max` config options.

If this feature is enabled, Synapse will regularly look for and purge events
which are older than the room's maximum retention period. Synapse will also
filter events received over federation so that events that should have been 
purged are ignored and not stored again. 

The message retention policies feature is disabled by default.

This setting has the following sub-options:
* `default_policy`: Default retention policy. If set, Synapse will apply it to rooms that lack the
   'm.room.retention' state event. This option is further specified by the 
   `min_lifetime` and `max_lifetime` sub-options associated with it. Note that the 
    value of `min_lifetime` doesn't matter much because Synapse doesn't take it into account yet. 

* `allowed_lifetime_min` and `allowed_lifetime_max`: Retention policy limits. If 
   set, and the state of a room contains a `m.room.retention` event in its state 
   which contains a `min_lifetime` or a `max_lifetime` that's out of these bounds,
   Synapse will cap the room's policy to these limits when running purge jobs.

* `purge_jobs` and the associated `shortest_max_lifetime` and `longest_max_lifetime` sub-options:
   Server admins can define the settings of the background jobs purging the
   events whose lifetime has expired under the `purge_jobs` section.
   
  If no configuration is provided for this option, a single job will be set up to delete
  expired events in every room daily.

  Each job's configuration defines which range of message lifetimes the job
  takes care of. For example, if `shortest_max_lifetime` is '2d' and
  `longest_max_lifetime` is '3d', the job will handle purging expired events in
  rooms whose state defines a `max_lifetime` that's both higher than 2 days, and
  lower than or equal to 3 days. Both the minimum and the maximum value of a
  range are optional, e.g. a job with no `shortest_max_lifetime` and a
  `longest_max_lifetime` of '3d' will handle every room with a retention policy
  whose `max_lifetime` is lower than or equal to three days.
  
  The rationale for this per-job configuration is that some rooms might have a
  retention policy with a low `max_lifetime`, where history needs to be purged
  of outdated messages on a more frequent basis than for the rest of the rooms
  (e.g. every 12h), but not want that purge to be performed by a job that's
  iterating over every room it knows, which could be heavy on the server.

  If any purge job is configured, it is strongly recommended to have at least
  a single job with neither `shortest_max_lifetime` nor `longest_max_lifetime`
  set, or one job without `shortest_max_lifetime` and one job without
  `longest_max_lifetime` set. Otherwise some rooms might be ignored, even if
  `allowed_lifetime_min` and `allowed_lifetime_max` are set, because capping a
  room's policy to these values is done after the policies are retrieved from
  Synapse's database (which is done using the range specified in a purge job's
  configuration).

Example configuration:
```yaml
retention:
  enabled: true
  default_policy:
    min_lifetime: 1d
    max_lifetime: 1y
  allowed_lifetime_min: 1d
  allowed_lifetime_max: 1y
  purge_jobs:
    - longest_max_lifetime: 3d
      interval: 12h
    - shortest_max_lifetime: 3d
      interval: 1d  
```
---
## TLS ##

Options related to TLS.

---
Config option: `tls_certificate_path`

This option specifies a PEM-encoded X509 certificate for TLS.
This certificate, as of Synapse 1.0, will need to be a valid and verifiable
certificate, signed by a recognised Certificate Authority. Defaults to none. 

Be sure to use a `.pem` file that includes the full certificate chain including
any intermediate certificates (for instance, if using certbot, use
`fullchain.pem` as your certificate, not `cert.pem`). 

Example configuration:
```yaml
tls_certificate_path: "CONFDIR/SERVERNAME.tls.crt"
```
---
Config option: `tls_private_key_path`

PEM-encoded private key for TLS. Defaults to none. 

Example configuration:
```yaml
tls_private_key_path: "CONFDIR/SERVERNAME.tls.key"
```
---
Config option: `federation_verify_certificates`
Whether to verify TLS server certificates for outbound federation requests.

Defaults to true. To disable certificate verification, set the option to false.

Example configuration:
```yaml
federation_verify_certificates: false
```
---
Config option: `federation_client_minimum_tls_version`

The minimum TLS version that will be used for outbound federation requests.

Defaults to `1`. Configurable to `1`, `1.1`, `1.2`, or `1.3`. Note
that setting this value higher than `1.2` will prevent federation to most
of the public Matrix network: only configure it to `1.3` if you have an
entirely private federation setup and you can ensure TLS 1.3 support.

Example configuration:
```yaml
federation_client_minimum_tls_version: 1.2
```
---
Config option: `federation_certificate_verification_whitelist`

Skip federation certificate verification on a given whitelist
of domains.

This setting should only be used in very specific cases, such as
federation over Tor hidden services and similar. For private networks
of homeservers, you likely want to use a private CA instead.

Only effective if `federation_verify_certicates` is `true`.

Example configuration:
```yaml
federation_certificate_verification_whitelist:
  - lon.example.com
  - "*.domain.com"
  - "*.onion"
```
---
Config option: `federation_custom_ca_list`

List of custom certificate authorities for federation traffic.

This setting should only normally be used within a private network of
homeservers.

Note that this list will replace those that are provided by your
operating environment. Certificates must be in PEM format.

Example configuration:
```yaml
federation_custom_ca_list:
  - myCA1.pem
  - myCA2.pem
  - myCA3.pem
```
---
## Federation ##

Options related to federation.

---
Config option: `federation_domain_whitelist`

Restrict federation to the given whitelist of domains.
N.B. we recommend also firewalling your federation listener to limit
inbound federation traffic as early as possible, rather than relying
purely on this application-layer restriction.  If not specified, the
default is to whitelist everything.

Example configuration:
```yaml
federation_domain_whitelist:
  - lon.example.com
  - nyc.example.com
  - syd.example.com
```
---
Config option: `federation_metrics_domains`

Report prometheus metrics on the age of PDUs being sent to and received from
the given domains. This can be used to give an idea of "delay" on inbound
and outbound federation, though be aware that any delay can be due to problems
at either end or with the intermediate network.

By default, no domains are monitored in this way.

Example configuration:
```yaml
federation_metrics_domains:
  - matrix.org
  - example.com
```
---
Config option: `allow_profile_lookup_over_federation`

Set to false to disable profile lookup over federation. By default, the
Federation API allows other homeservers to obtain profile data of any user
on this homeserver.

Example configuration:
```yaml
allow_profile_lookup_over_federation: false
```
---
Config option: `allow_device_name_lookup_over_federation`

Set this option to true to allow device display name lookup over federation. By default, the
Federation API prevents other homeservers from obtaining the display names of any user devices
on this homeserver.

Example configuration:
```yaml
allow_device_name_lookup_over_federation: true
```
---
## Caching ##

Options related to caching

---
Config option: `event_cache_size`

The number of events to cache in memory. Not affected by
`caches.global_factor`. Defaults to 10K.

Example configuration:
```yaml
event_cache_size: 15K
```
---
Config option: `cache` and associated values

A cache 'factor' is a multiplier that can be applied to each of
Synapse's caches in order to increase or decrease the maximum
number of entries that can be stored.

Caching can be configured through the following sub-options:

* `global_factor`: Controls the global cache factor, which is the default cache factor
  for all caches if a specific factor for that cache is not otherwise
  set.

  This can also be set by the `SYNAPSE_CACHE_FACTOR` environment
  variable. Setting by environment variable takes priority over
  setting through the config file.
  
  Defaults to 0.5, which will halve the size of all caches.

* `per_cache_factors`: A dictionary of cache name to cache factor for that individual
   cache. Overrides the global cache factor for a given cache.
  
   These can also be set through environment variables comprised
   of `SYNAPSE_CACHE_FACTOR_` + the name of the cache in capital
   letters and underscores. Setting by environment variable
   takes priority over setting through the config file.
   Ex. `SYNAPSE_CACHE_FACTOR_GET_USERS_WHO_SHARE_ROOM_WITH_USER=2.0`
  
   Some caches have '*' and other characters that are not
   alphanumeric or underscores. These caches can be named with or
   without the special characters stripped. For example, to specify
   the cache factor for `*stateGroupCache*` via an environment
   variable would be `SYNAPSE_CACHE_FACTOR_STATEGROUPCACHE=2.0`.
 
* `expire_caches`: Controls whether cache entries are evicted after a specified time
   period. Defaults to true. Set to false to disable this feature. Note that never expiring
   caches may result in excessive memory usage. 

* `cache_entry_ttl`: If `expire_caches` is enabled, this flag controls how long an entry can
  be in a cache without having been accessed before being evicted.
  Defaults to 30m. 

* `sync_response_cache_duration`: Controls how long the results of a /sync request are
  cached for after a successful response is returned. A higher duration can help clients
  with intermittent connections, at the cost of higher memory usage.
  By default, this is zero, which means that sync responses are not cached
  at all.
* `cache_autotuning` and its sub-options `max_cache_memory_usage`, `target_cache_memory_usage`, and
   `min_cache_ttl` work in conjunction with each other to maintain a balance between cache memory 
   usage and cache entry availability. You must be using [jemalloc](https://github.com/matrix-org/synapse#help-synapse-is-slow-and-eats-all-my-ramcpu) 
   to utilize this option, and all three of the options must be specified for this feature to work.
     * `max_cache_memory_usage` sets a ceiling on how much memory the cache can use before caches begin to be continuously evicted.
        They will continue to be evicted until the memory usage drops below the `target_memory_usage`, set in
        the flag below, or until the `min_cache_ttl` is hit.
     * `target_memory_usage` sets a rough target for the desired memory usage of the caches.
     * `min_cache_ttl` sets a limit under which newer cache entries are not evicted and is only applied when
        caches are actively being evicted/`max_cache_memory_usage` has been exceeded. This is to protect hot caches
        from being emptied while Synapse is evicting due to memory.

Example configuration:
```yaml
caches:
  global_factor: 1.0
  per_cache_factors:
    get_users_who_share_room_with_user: 2.0
  sync_response_cache_duration: 2m
  cache_autotuning:
    max_cache_memory_usage: 1024M
    target_cache_memory_usage: 758M
    min_cache_ttl: 5m
```

### Reloading cache factors

The cache factors (i.e. `caches.global_factor` and `caches.per_cache_factors`)  may be reloaded at any time by sending a
[`SIGHUP`](https://en.wikipedia.org/wiki/SIGHUP) signal to Synapse using e.g.

```commandline
kill -HUP [PID_OF_SYNAPSE_PROCESS]
```

If you are running multiple workers, you must individually update the worker 
config file and send this signal to each worker process.

If you're using the [example systemd service](https://github.com/matrix-org/synapse/blob/develop/contrib/systemd/matrix-synapse.service)
file in Synapse's `contrib` directory, you can send a `SIGHUP` signal by using
`systemctl reload matrix-synapse`.

---
## Database ##
Config options related to database settings.

---
Config option: `database`

The `database` setting defines the database that synapse uses to store all of
its data.

Associated sub-options:

* `name`: this option specifies the database engine to use: either `sqlite3` (for SQLite)
  or `psycopg2` (for PostgreSQL). If no name is specified Synapse will default to SQLite. 

* `txn_limit` gives the maximum number of transactions to run per connection
  before reconnecting. Defaults to 0, which means no limit.

* `allow_unsafe_locale` is an option specific to Postgres. Under the default behavior, Synapse will refuse to
  start if the postgres db is set to a non-C locale. You can override this behavior (which is *not* recommended)
  by setting `allow_unsafe_locale` to true. Note that doing so may corrupt your database. You can find more information
  [here](../../postgres.md#fixing-incorrect-collate-or-ctype) and [here](https://wiki.postgresql.org/wiki/Locale_data_changes).

* `args` gives options which are passed through to the database engine,
  except for options starting with `cp_`, which are used to configure the Twisted
  connection pool. For a reference to valid arguments, see:
    * for [sqlite](https://docs.python.org/3/library/sqlite3.html#sqlite3.connect)
    * for [postgres](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS)
    * for [the connection pool](https://twistedmatrix.com/documents/current/api/twisted.enterprise.adbapi.ConnectionPool.html#__init__)

For more information on using Synapse with Postgres,
see [here](../../postgres.md).

Example SQLite configuration:
```
database:
  name: sqlite3
  args:
    database: /path/to/homeserver.db
```

Example Postgres configuration:
```
database:
  name: psycopg2
  txn_limit: 10000
  args:
    user: synapse_user
    password: secretpassword
    database: synapse
    host: localhost
    port: 5432
    cp_min: 5
    cp_max: 10
```
---
## Logging ##
Config options related to logging. 

---
Config option: `log_config`

This option specifies a yaml python logging config file as described [here](https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema).

Example configuration:
```yaml
log_config: "CONFDIR/SERVERNAME.log.config"
```
---
## Ratelimiting ##
Options related to ratelimiting in Synapse. 

Each ratelimiting configuration is made of two parameters:
   - `per_second`: number of requests a client can send per second.
   - `burst_count`: number of requests a client can send before being throttled.
---
Config option: `rc_message`


Ratelimiting settings for client messaging.
   
This is a ratelimiting option for messages that ratelimits sending based on the account the client
is using. It defaults to: `per_second: 0.2`, `burst_count: 10`.

Example configuration:
```yaml
rc_message:
  per_second: 0.5
  burst_count: 15
```
---
Config option: `rc_registration`

This option ratelimits registration requests based on the client's IP address.
It defaults to `per_second: 0.17`, `burst_count: 3`. 

Example configuration:
```yaml
rc_registration:
  per_second: 0.15
  burst_count: 2
```
---
Config option: `rc_registration_token_validity`

This option checks the validity of registration tokens that ratelimits requests based on 
the client's IP address.
Defaults to `per_second: 0.1`, `burst_count: 5`.

Example configuration:
```yaml
rc_registration_token_validity:
  per_second: 0.3
  burst_count: 6
```   
---
Config option: `rc_login`

This option specifies several limits for login:
* `address` ratelimits login requests based on the client's IP
      address. Defaults to `per_second: 0.17`, `burst_count: 3`.
    
* `account` ratelimits login requests based on the account the
  client is attempting to log into. Defaults to `per_second: 0.17`,
  `burst_count: 3`.
    
* `failted_attempts` ratelimits login requests based on the account the
  client is attempting to log into, based on the amount of failed login
  attempts for this account. Defaults to `per_second: 0.17`, `burst_count: 3`.

Example configuration:
```yaml
rc_login:
  address:
    per_second: 0.15
    burst_count: 5
  account:
    per_second: 0.18
    burst_count: 4
  failed_attempts:
    per_second: 0.19
    burst_count: 7
```
---
Config option: `rc_admin_redaction`

This option sets ratelimiting redactions by room admins. If this is not explicitly 
set then it uses the same ratelimiting as per `rc_message`. This is useful
to allow room admins to deal with abuse quickly. 

Example configuration:
```yaml
rc_admin_redaction:
  per_second: 1
  burst_count: 50
```
---
Config option: `rc_joins`

This option allows for ratelimiting number of rooms a user can join. This setting has the following sub-options:

* `local`: ratelimits when users are joining rooms the server is already in. 
   Defaults to `per_second: 0.1`, `burst_count: 10`.

* `remote`: ratelimits when users are trying to join rooms not on the server (which
  can be more computationally expensive than restricting locally). Defaults to
  `per_second: 0.01`, `burst_count: 10` 

Example configuration:
```yaml
rc_joins:
  local:
    per_second: 0.2
    burst_count: 15
  remote:
    per_second: 0.03
    burst_count: 12
```
---
Config option: `rc_3pid_validation`

This option ratelimits how often a user or IP can attempt to validate a 3PID.
Defaults to `per_second: 0.003`, `burst_count: 5`.

Example configuration:
```yaml
rc_3pid_validation:
  per_second: 0.003
  burst_count: 5
```
---
Config option: `rc_invites`

This option sets ratelimiting how often invites can be sent in a room or to a 
specific user. `per_room` defaults to `per_second: 0.3`, `burst_count: 10` and
`per_user` defaults to `per_second: 0.003`, `burst_count: 5`. 

Client requests that invite user(s) when [creating a
room](https://spec.matrix.org/v1.2/client-server-api/#post_matrixclientv3createroom)
will count against the `rc_invites.per_room` limit, whereas
client requests to [invite a single user to a
room](https://spec.matrix.org/v1.2/client-server-api/#post_matrixclientv3roomsroomidinvite)
will count against both the `rc_invites.per_user` and `rc_invites.per_room` limits.

Federation requests to invite a user will count against the `rc_invites.per_user`
limit only, as Synapse presumes ratelimiting by room will be done by the sending server.

The `rc_invites.per_user` limit applies to the *receiver* of the invite, rather than the
sender, meaning that a `rc_invite.per_user.burst_count` of 5 mandates that a single user
cannot *receive* more than a burst of 5 invites at a time.

Example configuration:
```yaml
rc_invites:
  per_room:
    per_second: 0.5
    burst_count: 5
  per_user:
    per_second: 0.004
    burst_count: 3
```
---
Config option: `rc_third_party_invite`

This option ratelimits 3PID invites (i.e. invites sent to a third-party ID
such as an email address or a phone number) based on the account that's
sending the invite. Defaults to `per_second: 0.2`, `burst_count: 10`.

Example configuration:
```yaml
rc_third_party_invite:
  per_second: 0.2
  burst_count: 10
```
---
Config option: `rc_federation`

Defines limits on federation requests. 

The `rc_federation` configuration has the following sub-options:
* `window_size`: window size in milliseconds. Defaults to 1000.
* `sleep_limit`: number of federation requests from a single server in
   a window before the server will delay processing the request. Defaults to 10.
* `sleep_delay`: duration in milliseconds to delay processing events
   from remote servers by if they go over the sleep limit. Defaults to 500.
* `reject_limit`: maximum number of concurrent federation requests
   allowed from a single server. Defaults to 50.
* `concurrent`: number of federation requests to concurrently process
   from a single server. Defaults to 3.

Example configuration:
```yaml
rc_federation:
  window_size: 750
  sleep_limit: 15
  sleep_delay: 400
  reject_limit: 40
  concurrent: 5
```
---
Config option: `federation_rr_transactions_per_room_per_second`

Sets outgoing federation transaction frequency for sending read-receipts,
per-room.

If we end up trying to send out more read-receipts, they will get buffered up
into fewer transactions. Defaults to 50. 

Example configuration:
```yaml
federation_rr_transactions_per_room_per_second: 40
```
---
## Media Store ##
Config options relating to Synapse media store.

---
Config option: `enable_media_repo` 

Enable the media store service in the Synapse master. Defaults to true. 
Set to false if you are using a separate media store worker.

Example configuration:
```yaml
enable_media_repo: false
```
---
Config option: `media_store_path`

Directory where uploaded images and attachments are stored.

Example configuration:
```yaml
media_store_path: "DATADIR/media_store"
```
---
Config option: `media_storage_providers`

Media storage providers allow media to be stored in different
locations. Defaults to none. Associated sub-options are:
* `module`: type of resource, e.g. `file_system`.
* `store_local`: whether to store newly uploaded local files
* `store_remote`: whether to store newly downloaded local files
* `store_synchronous`: whether to wait for successful storage for local uploads
* `config`: sets a path to the resource through the `directory` option 

Example configuration:
```yaml
media_storage_providers:
  - module: file_system
    store_local: false
    store_remote: false
    store_synchronous: false
    config:
       directory: /mnt/some/other/directory
```
---
Config option: `max_upload_size`

The largest allowed upload size in bytes.

If you are using a reverse proxy you may also need to set this value in
your reverse proxy's config. Defaults to 50M. Notably Nginx has a small max body size by default.
See [here](../../reverse_proxy.md) for more on using a reverse proxy with Synapse. 

Example configuration:
```yaml
max_upload_size: 60M
```
---
Config option: `max_image_pixels`

Maximum number of pixels that will be thumbnailed. Defaults to 32M.

Example configuration:
```yaml
max_image_pixels: 35M
```
---
Config option: `dynamic_thumbnails`

Whether to generate new thumbnails on the fly to precisely match
the resolution requested by the client. If true then whenever
a new resolution is requested by the client the server will
generate a new thumbnail. If false the server will pick a thumbnail
from a precalculated list. Defaults to false. 

Example configuration:
```yaml
dynamic_thumbnails: true
```
---
Config option: `thumbnail_sizes`  

List of thumbnails to precalculate when an image is uploaded. Associated sub-options are:
* `width`
* `height`
* `method`: i.e. `crop`, `scale`, etc.

Example configuration:
```yaml
thumbnail_sizes:
  - width: 32
    height: 32
    method: crop
  - width: 96
    height: 96
    method: crop
  - width: 320
    height: 240
    method: scale
  - width: 640
    height: 480
    method: scale
  - width: 800
    height: 600
    method: scale
```
Config option: `url_preview_enabled`

This setting determines whether the preview URL API is enabled.
It is disabled by default. Set to true to enable. If enabled you must specify a
`url_preview_ip_range_blacklist` blacklist.

Example configuration:
```yaml
url_preview_enabled: true
```
---
Config option: `url_preview_ip_range_blacklist`

List of IP address CIDR ranges that the URL preview spider is denied
from accessing.  There are no defaults: you must explicitly
specify a list for URL previewing to work.  You should specify any
internal services in your network that you do not want synapse to try
to connect to, otherwise anyone in any Matrix room could cause your
synapse to issue arbitrary GET requests to your internal services,
causing serious security issues.

(0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
listed here, since they correspond to unroutable addresses.)

This must be specified if `url_preview_enabled` is set. It is recommended that
you use the following example list as a starting point.

Note: The value is ignored when an HTTP proxy is in use.

Example configuration:
```yaml
url_preview_ip_range_blacklist:
  - '127.0.0.0/8'
  - '10.0.0.0/8'
  - '172.16.0.0/12'
  - '192.168.0.0/16'
  - '100.64.0.0/10'
  - '192.0.0.0/24'
  - '169.254.0.0/16'
  - '192.88.99.0/24'
  - '198.18.0.0/15'
  - '192.0.2.0/24'
  - '198.51.100.0/24'
  - '203.0.113.0/24'
  - '224.0.0.0/4'
  - '::1/128'
  - 'fe80::/10'
  - 'fc00::/7'
  - '2001:db8::/32'
  - 'ff00::/8'
  - 'fec0::/10'
```
----
Config option: `url_preview_ip_range_whitelist`

This option sets a list of IP address CIDR ranges that the URL preview spider is allowed
to access even if they are specified in `url_preview_ip_range_blacklist`.
This is useful for specifying exceptions to wide-ranging blacklisted
target IP ranges - e.g. for enabling URL previews for a specific private
website only visible in your network. Defaults to none. 

Example configuration:
```yaml
url_preview_ip_range_whitelist:
   - '192.168.1.1'
```
---
Config option: `url_preview_url_blacklist`

Optional list of URL matches that the URL preview spider is
denied from accessing.  You should use `url_preview_ip_range_blacklist`
in preference to this, otherwise someone could define a public DNS
entry that points to a private IP address and circumvent the blacklist.
This is more useful if you know there is an entire shape of URL that
you know that will never want synapse to try to spider.

Each list entry is a dictionary of url component attributes as returned
by urlparse.urlsplit as applied to the absolute form of the URL.  See 
[here](https://docs.python.org/2/library/urlparse.html#urlparse.urlsplit) for more
information. Some examples are:

* `username`
* `netloc`
* `scheme`
* `path`

The values of the dictionary are treated as a filename match pattern
applied to that component of URLs, unless they start with a ^ in which
case they are treated as a regular expression match.  If all the
specified component matches for a given list item succeed, the URL is
blacklisted.

Example configuration:
```yaml
url_preview_url_blacklist:
  # blacklist any URL with a username in its URI
  - username: '*'

  # blacklist all *.google.com URLs
  - netloc: 'google.com'
  - netloc: '*.google.com'

  # blacklist all plain HTTP URLs
  - scheme: 'http'

  # blacklist http(s)://www.acme.com/foo
  - netloc: 'www.acme.com'
    path: '/foo'

  # blacklist any URL with a literal IPv4 address
  - netloc: '^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$'
```
---
Config option: `max_spider_size`

The largest allowed URL preview spidering size in bytes. Defaults to 10M.

Example configuration:
```yaml
max_spider_size: 8M
```
---
Config option: `url_preview_language`

A list of values for the Accept-Language HTTP header used when
downloading webpages during URL preview generation. This allows
Synapse to specify the preferred languages that URL previews should
be in when communicating with remote servers.

Each value is a IETF language tag; a 2-3 letter identifier for a
language, optionally followed by subtags separated by '-', specifying
a country or region variant.

Multiple values can be provided, and a weight can be added to each by
using quality value syntax (;q=). '*' translates to any language.

Defaults to "en".

Example configuration:
```yaml
 url_preview_accept_language:
   - en-UK
   - en-US;q=0.9
   - fr;q=0.8
   - *;q=0.7
```
----
Config option: `oembed`

oEmbed allows for easier embedding content from a website. It can be
used for generating URLs previews of services which support it. A default list of oEmbed providers
is included with Synapse. Set `disable_default_providers` to true to disable using
these default oEmbed URLs. Use `additional_providers` to specify additional files with oEmbed configuration (each 
should be in the form of providers.json). By default this list is empty. 

Example configuration:
```yaml
oembed:
  disable_default_providers: true
  additional_providers:
    - oembed/my_providers.json
```
---
## Captcha ##

See [here](../../CAPTCHA_SETUP.md) for full details on setting up captcha.

---
Config option: `recaptcha_public_key`

This homeserver's ReCAPTCHA public key. Must be specified if `enable_registration_captcha` is 
enabled.

Example configuration:
```yaml
recaptcha_public_key: "YOUR_PUBLIC_KEY"
```
---
Config option: `recaptcha_private_key` 

This homeserver's ReCAPTCHA private key. Must be specified if `enable_registration_captcha` is 
enabled.

Example configuration:
```yaml
recaptcha_private_key: "YOUR_PRIVATE_KEY"
```
---
Config option: `enable_registration_captcha`

Set to true to enable ReCaptcha checks when registering, preventing signup
unless a captcha is answered. Requires a valid ReCaptcha public/private key. 
Defaults to false.

Example configuration:
```yaml
enable_registration_captcha: true
```
---
Config option: `recaptcha_siteverify_api`

The API endpoint to use for verifying `m.login.recaptcha` responses.
Defaults to `https://www.recaptcha.net/recaptcha/api/siteverify`.

Example configuration:
```yaml
recaptcha_siteverify_api: "https://my.recaptcha.site"
```
---
## TURN ##
Options related to adding a TURN server to Synapse.

---
Config option: `turn_uris`

The public URIs of the TURN server to give to clients.

Example configuration:
```yaml
turn_uris: [turn:example.org]
```
---
Config option: `turn_shared_secret`

The shared secret used to compute passwords for the TURN server.

Example configuration:
```yaml
turn_shared_secret: "YOUR_SHARED_SECRET"
```
----
Config options: `turn_username` and `turn_password`

The Username and password if the TURN server needs them and does not use a token.

Example configuration:
```yaml
turn_username: "TURNSERVER_USERNAME"
turn_password: "TURNSERVER_PASSWORD"
```
---
Config option: `turn_user_lifetime`

How long generated TURN credentials last. Defaults to 1h.

Example configuration:
```yaml
turn_user_lifetime: 2h
```
---
Config option: `turn_allow_guests`

Whether guests should be allowed to use the TURN server. This defaults to true, otherwise
VoIP will be unreliable for guests. However, it does introduce a slight security risk as
it allows users to connect to arbitrary endpoints without having first signed up for a valid account (e.g. by passing a CAPTCHA).

Example configuration:
```yaml
turn_allow_guests: false
```
---
## Registration ##

Registration can be rate-limited using the parameters in the [Ratelimiting](#ratelimiting) section of this manual.

---
Config option: `enable_registration`

Enable registration for new users. Defaults to false. It is highly recommended that if you enable registration,
you use either captcha, email, or token-based verification to verify that new users are not bots. In order to enable registration 
without any verification, you must also set `enable_registration_without_verification` to true.

Example configuration:
```yaml
enable_registration: true
```
---
Config option: `enable_registration_without_verification`
Enable registration without email or captcha verification. Note: this option is *not* recommended,
as registration without verification is a known vector for spam and abuse. Defaults to false. Has no effect
unless `enable_registration` is also enabled.

Example configuration:
```yaml
enable_registration_without_verification: true
```
---
Config option: `session_lifetime`

Time that a user's session remains valid for, after they log in.

Note that this is not currently compatible with guest logins.

Note also that this is calculated at login time: changes are not applied retrospectively to users who have already 
logged in.

By default, this is infinite.

Example configuration:
```yaml
session_lifetime: 24h
```
----
Config option: `refresh_access_token_lifetime`

Time that an access token remains valid for, if the session is using refresh tokens.

For more information about refresh tokens, please see the [manual](user_authentication/refresh_tokens.md).

Note that this only applies to clients which advertise support for refresh tokens.

Note also that this is calculated at login time and refresh time: changes are not applied to 
existing sessions until they are refreshed.

By default, this is 5 minutes.

Example configuration:
```yaml
refreshable_access_token_lifetime: 10m
```
---
Config option: `refresh_token_lifetime: 24h`

Time that a refresh token remains valid for (provided that it is not
exchanged for another one first).
This option can be used to automatically log-out inactive sessions.
Please see the manual for more information.

Note also that this is calculated at login time and refresh time:
changes are not applied to existing sessions until they are refreshed.

By default, this is infinite.

Example configuration:
```yaml
refresh_token_lifetime: 24h
```
---
Config option: `nonrefreshable_access_token_lifetime`

Time that an access token remains valid for, if the session is NOT
using refresh tokens.

Please note that not all clients support refresh tokens, so setting
this to a short value may be inconvenient for some users who will
then be logged out frequently.

Note also that this is calculated at login time: changes are not applied
retrospectively to existing sessions for users that have already logged in.

By default, this is infinite.

Example configuration:
```yaml
nonrefreshable_access_token_lifetime: 24h
```
---
Config option: `registrations_require_3pid`

If this is set, the user must provide all of the specified types of 3PID when registering.

Example configuration:
```yaml
registrations_require_3pid:
  - email
  - msisdn
```
---
Config option: `disable_msisdn_registration`

Explicitly disable asking for MSISDNs from the registration
flow (overrides `registrations_require_3pid` if MSISDNs are set as required).

Example configuration:
```yaml
disable_msisdn_registration: true
```
---
Config option: `allowed_local_3pids`

Mandate that users are only allowed to associate certain formats of
3PIDs with accounts on this server, as specified by the `medium` and `pattern` sub-options.

Example configuration:
```yaml
allowed_local_3pids:
  - medium: email
    pattern: '^[^@]+@matrix\.org$'
  - medium: email
    pattern: '^[^@]+@vector\.im$'
  - medium: msisdn
    pattern: '\+44'
```
---
Config option: `enable_3pid_lookup`

Enable 3PIDs lookup requests to identity servers from this server. Defaults to true.

Example configuration:
```yaml
enable_3pid_lookup: false
```
---
Config option: `registration_requires_token`

Require users to submit a token during registration.
Tokens can be managed using the admin [API](../administration/admin_api/registration_tokens.md).
Note that `enable_registration` must be set to true.
Disabling this option will not delete any tokens previously generated.
Defaults to false. Set to true to enable.  

Example configuration:
```yaml
registration_requires_token: true
```
---
Config option: `registration_shared_secret`

If set, allows registration of standard or admin accounts by anyone who
has the shared secret, even if registration is otherwise disabled.

Example configuration:
```yaml
registration_shared_secret: <PRIVATE STRING>
```
---
Config option: `bcrypt_rounds`

Set the number of bcrypt rounds used to generate password hash.
Larger numbers increase the work factor needed to generate the hash.
The default number is 12 (which equates to 2^12 rounds).
N.B. that increasing this will exponentially increase the time required
to register or login - e.g. 24 => 2^24 rounds which will take >20 mins.
Example configuration:
```yaml
bcrypt_rounds: 14
```
---
Config option: `allow_guest_access`

Allows users to register as guests without a password/email/etc, and
participate in rooms hosted on this server which have been made
accessible to anonymous users. Defaults to false.

Example configuration:
```yaml
allow_guest_access: true
```
---
Config option: `default_identity_server`

The identity server which we suggest that clients should use when users log
in on this server.

(By default, no suggestion is made, so it is left up to the client.
This setting is ignored unless `public_baseurl` is also explicitly set.)

Example configuration:
```yaml
default_identity_server: https://matrix.org
```
---
Config option: `account_threepid_delegates`

Handle threepid (email/phone etc) registration and password resets through a set of
*trusted* identity servers. Note that this allows the configured identity server to
reset passwords for accounts!

Be aware that if `email` is not set, and SMTP options have not been
configured in the email config block, registration and user password resets via
email will be globally disabled.

Additionally, if `msisdn` is not set, registration and password resets via msisdn
will be disabled regardless, and users will not be able to associate an msisdn
identifier to their account. This is due to Synapse currently not supporting
any method of sending SMS messages on its own.

To enable using an identity server for operations regarding a particular third-party
identifier type, set the value to the URL of that identity server as shown in the
examples below.

Servers handling the these requests must answer the `/requestToken` endpoints defined
by the Matrix Identity Service API [specification](https://matrix.org/docs/spec/identity_service/latest).

Example configuration:
```yaml
account_threepid_delegates:
    email: https://example.com     # Delegate email sending to example.com
    msisdn: http://localhost:8090  # Delegate SMS sending to this local process
```
---
Config option: `enable_set_displayname`

Whether users are allowed to change their displayname after it has
been initially set. Useful when provisioning users based on the
contents of a third-party directory.

Does not apply to server administrators. Defaults to true.

Example configuration:
```yaml
enable_set_displayname: false
```
---
Config option: `enable_set_avatar_url`

Whether users are allowed to change their avatar after it has been
initially set. Useful when provisioning users based on the contents
of a third-party directory.

Does not apply to server administrators. Defaults to true.

Example configuration:
```yaml
enable_set_avatar_url: false
```
---
Config option: `enable_3pid_changes`

Whether users can change the third-party IDs associated with their accounts
(email address and msisdn).

Defaults to true.

Example configuration:
```yaml
enable_3pid_changes: false
```
---
Config option: `auto_join_rooms`

Users who register on this homeserver will automatically be joined
to the rooms listed under this option.

By default, any room aliases included in this list will be created
as a publicly joinable room when the first user registers for the
homeserver. If the room already exists, make certain it is a publicly joinable
room, i.e. the join rule of the room must be set to 'public'. You can find more options
relating to auto-joining rooms below. 

Example configuration:
```yaml
auto_join_rooms:
  - "#exampleroom:example.com"
  - "#anotherexampleroom:example.com"
```
---
Config option: `autocreate_auto_join_rooms`

Where `auto_join_rooms` are specified, setting this flag ensures that
the rooms exist by creating them when the first user on the
homeserver registers.

By default the auto-created rooms are publicly joinable from any federated
server. Use the `autocreate_auto_join_rooms_federated` and
`autocreate_auto_join_room_preset` settings to customise this behaviour.

Setting to false means that if the rooms are not manually created,
users cannot be auto-joined since they do not exist.

Defaults to true.

Example configuration:
```yaml
autocreate_auto_join_rooms: false
```
---
Config option: `autocreate_auto_join_rooms_federated`

Whether the rooms listen in `auto_join_rooms` that are auto-created are available
via federation. Only has an effect if `autocreate_auto_join_rooms` is true.

Note that whether a room is federated cannot be modified after
creation.

Defaults to true: the room will be joinable from other servers.
Set to false to prevent users from other homeservers from
joining these rooms.

Example configuration:
```yaml
autocreate_auto_join_rooms_federated: false
```
---
Config option: `autocreate_auto_join_room_preset`

The room preset to use when auto-creating one of `auto_join_rooms`. Only has an
effect if `autocreate_auto_join_rooms` is true.

Possible values for this option are:
* "public_chat": the room is joinable by anyone, including
  federated servers if `autocreate_auto_join_rooms_federated` is true (the default).
* "private_chat": an invitation is required to join these rooms. 
* "trusted_private_chat": an invitation is required to join this room and the invitee is
  assigned a power level of 100 upon joining the room. 

If a value of "private_chat" or "trusted_private_chat" is used then
`auto_join_mxid_localpart` must also be configured.

Defaults to "public_chat".

Example configuration:
```yaml
autocreate_auto_join_room_preset: private_chat
```
---
Config option: `auto_join_mxid_localpart`

The local part of the user id which is used to create `auto_join_rooms` if
`autocreate_auto_join_rooms` is true. If this is not provided then the
initial user account that registers will be used to create the rooms.

The user id is also used to invite new users to any auto-join rooms which
are set to invite-only.

It *must* be configured if `autocreate_auto_join_room_preset` is set to
"private_chat" or "trusted_private_chat".

Note that this must be specified in order for new users to be correctly
invited to any auto-join rooms which have been set to invite-only (either
at the time of creation or subsequently).

Note that, if the room already exists, this user must be joined and
have the appropriate permissions to invite new members.

Example configuration:
```yaml
auto_join_mxid_localpart: system
```
---
Config option: `auto_join_rooms_for_guests`
 
When `auto_join_rooms` is specified, setting this flag to false prevents
guest accounts from being automatically joined to the rooms.

Defaults to true.

Example configuration:
```yaml
auto_join_rooms_for_guests: false
```
---
Config option: `inhibit_user_in_use_error`
 
Whether to inhibit errors raised when registering a new account if the user ID
already exists. If turned on, requests to `/register/available` will always
show a user ID as available, and Synapse won't raise an error when starting
a registration with a user ID that already exists. However, Synapse will still
raise an error if the registration completes and the username conflicts.

Defaults to false.

Example configuration:
```yaml
inhibit_user_in_use_error: true
```
---
## Metrics ###
Config options related to metrics.

---
Config option: `enable_metrics`

Set to true to enable collection and rendering of performance metrics. 
Defaults to false.

Example configuration:
```yaml
enable_metrics: true
```
---
Config option: `sentry`

Use this option to enable sentry integration. Provide the DSN assigned to you by sentry
with the `dsn` setting. 

NOTE: While attempts are made to ensure that the logs don't contain
any sensitive information, this cannot be guaranteed. By enabling
this option the sentry server may therefore receive sensitive 
information, and it in turn may then disseminate sensitive information
through insecure notification channels if so configured.

Example configuration:
```yaml
sentry:
    dsn: "..."
```
---
Config option: `metrics_flags`

Flags to enable Prometheus metrics which are not suitable to be
enabled by default, either for performance reasons or limited use.
Currently the only option is `known_servers`, which publishes 
`synapse_federation_known_servers`, a gauge of the number of
servers this homeserver knows about, including itself. May cause
performance problems on large homeservers.

Example configuration:
```yaml
metrics_flags:
    known_servers: true
```
---
Config option: `report_stats`

Whether or not to report anonymized homeserver usage statistics. This is originally
set when generating the config. Set this option to true or false to change the current
behavior. 

Example configuration:
```yaml
report_stats: true
```
---
Config option: `report_stats_endpoint`

The endpoint to report the anonymized homeserver usage statistics to.
Defaults to https://matrix.org/report-usage-stats/push

Example configuration:
```yaml
report_stats_endpoint: https://example.com/report-usage-stats/push
```
---
## API Configuration ##
Config settings related to the client/server API

---
Config option: `room_prejoin_state:`

Controls for the state that is shared with users who receive an invite
to a room. By default, the following state event types are shared with users who 
receive invites to the room:
- m.room.join_rules
- m.room.canonical_alias
- m.room.avatar
- m.room.encryption
- m.room.name
- m.room.create
- m.room.topic

To change the default behavior, use the following sub-options:
* `disable_default_event_types`: set to true to disable the above defaults. If this 
   is enabled, only the event types listed in `additional_event_types` are shared.
   Defaults to false.
* `additional_event_types`: Additional state event types to share with users when they are invited
   to a room. By default, this list is empty (so only the default event types are shared).

Example configuration:
```yaml
room_prejoin_state:
   disable_default_event_types: true
   additional_event_types:
     - org.example.custom.event.type
     - m.room.join_rules
```
---
Config option: `track_puppeted_user_ips`

We record the IP address of clients used to access the API for various
reasons, including displaying it to the user in the "Where you're signed in"
dialog.

By default, when puppeting another user via the admin API, the client IP
address is recorded against the user who created the access token (ie, the
admin user), and *not* the puppeted user.

Set this option to true to also record the IP address against the puppeted
user. (This also means that the puppeted user will count as an "active" user
for the purpose of monthly active user tracking - see `limit_usage_by_mau` etc
above.)

Example configuration:
```yaml
track_puppeted_user_ips: true
```
---
Config option: `app_service_config_files`

A list of application service config files to use.

Example configuration:
```yaml
app_service_config_files:
  - app_service_1.yaml
  - app_service_2.yaml
```
---
Config option: `track_appservice_user_ips`

Defaults to false. Set to true to enable tracking of application service IP addresses.
Implicitly enables MAU tracking for application service users.

Example configuration:
```yaml
track_appservice_user_ips: true
```
---
Config option: `macaroon_secret_key`

A secret which is used to sign access tokens. If none is specified,
the `registration_shared_secret` is used, if one is given; otherwise,
a secret key is derived from the signing key.

Example configuration:
```yaml
macaroon_secret_key: <PRIVATE STRING>
```
---
Config option: `form_secret`

A secret which is used to calculate HMACs for form values, to stop
falsification of values. Must be specified for the User Consent
forms to work.

Example configuration:
```yaml
form_secret: <PRIVATE STRING>
```
---
## Signing Keys ##
Config options relating to signing keys

---
Config option: `signing_key_path`

Path to the signing key to sign messages with.

Example configuration:
```yaml
signing_key_path: "CONFDIR/SERVERNAME.signing.key"
```
--- 
Config option: `old_signing_keys`

The keys that the server used to sign messages with but won't use
to sign new messages. For each key, `key` should be the base64-encoded public key, and
`expired_ts`should be the time (in milliseconds since the unix epoch) that
it was last used.

It is possible to build an entry from an old `signing.key` file using the
`export_signing_key` script which is provided with synapse.

Example configuration:
```yaml
old_signing_keys:
  "ed25519:id": { key: "base64string", expired_ts: 123456789123 }
```
---
Config option: `key_refresh_interval`

How long key response published by this server is valid for.
Used to set the `valid_until_ts` in `/key/v2` APIs.
Determines how quickly servers will query to check which keys
are still valid. Defaults to 1d.

Example configuration:
```yaml
key_refresh_interval: 2d
```
---
Config option: `trusted_key_servers:`

The trusted servers to download signing keys from.

When we need to fetch a signing key, each server is tried in parallel.

Normally, the connection to the key server is validated via TLS certificates.
Additional security can be provided by configuring a `verify key`, which
will make synapse check that the response is signed by that key.

This setting supercedes an older setting named `perspectives`. The old format
is still supported for backwards-compatibility, but it is deprecated.

`trusted_key_servers` defaults to matrix.org, but using it will generate a
warning on start-up. To suppress this warning, set
`suppress_key_server_warning` to true.

Options for each entry in the list include:
* `server_name`: the name of the server. Required.
* `verify_keys`: an optional map from key id to base64-encoded public key.
   If specified, we will check that the response is signed by at least
   one of the given keys.
* `accept_keys_insecurely`: a boolean. Normally, if `verify_keys` is unset,
   and `federation_verify_certificates` is not `true`, synapse will refuse 
   to start, because this would allow anyone who can spoof DNS responses
   to masquerade as the trusted key server. If you know what you are doing
   and are sure that your network environment provides a secure connection
   to the key server, you can set this to `true` to override this behaviour.

Example configuration #1:
```yaml
trusted_key_servers:
  - server_name: "my_trusted_server.example.com"
    verify_keys:
      "ed25519:auto": "abcdefghijklmnopqrstuvwxyzabcdefghijklmopqr"
  - server_name: "my_other_trusted_server.example.com"
```
Example configuration #2:
```yaml
trusted_key_servers:
  - server_name: "matrix.org"
```
---
Config option: `suppress_key_server_warning`

Set the following to true to disable the warning that is emitted when the
`trusted_key_servers` include 'matrix.org'. See above.

Example configuration:
```yaml
suppress_key_server_warning: true
```
---
Config option: `key_server_signing_keys_path`

The signing keys to use when acting as a trusted key server. If not specified
defaults to the server signing key.

Can contain multiple keys, one per line.

Example configuration:
```yaml
key_server_signing_keys_path: "key_server_signing_keys.key"
```
---
## Single sign-on integration ##

The following settings can be used to make Synapse use a single sign-on
provider for authentication, instead of its internal password database.

You will probably also want to set the following options to false to
disable the regular login/registration flows:
   * `enable_registration`
   * `password_config.enabled`

You will also want to investigate the settings under the "sso" configuration
section below.

---
Config option: `saml2_config`

Enable SAML2 for registration and login. Uses pysaml2. To learn more about pysaml and
to find a full list options for configuring pysaml, read the docs [here](https://pysaml2.readthedocs.io/en/latest/).

At least one of `sp_config` or `config_path` must be set in this section to
enable SAML login. You can either put your entire pysaml config inline using the `sp_config`
option, or you can specify a path to a psyaml config file with the sub-option `config_path`.
This setting has the following sub-options:

* `sp_config`: the configuration for the pysaml2 Service Provider. See pysaml2 docs for format of config.
   Default values will be used for the `entityid` and `service` settings,
   so it is not normally necessary to specify them unless you need to
   override them. Here are a few useful sub-options for configuring pysaml:
   * `metadata`: Point this to the IdP's metadata. You must provide either a local
      file via the `local` attribute or (preferably) a URL via the
      `remote` attribute.
   * `accepted_time_diff: 3`: Allowed clock difference in seconds between the homeserver and IdP.
      Defaults to 0.
   * `service`: By default, the user has to go to our login page first. If you'd like
     to allow IdP-initiated login, set `allow_unsolicited` to true under `sp` in the `service`
     section.
* `config_path`: specify a separate pysaml2 configuration file thusly: 
  `config_path: "CONFDIR/sp_conf.py"`
* `saml_session_lifetime`: The lifetime of a SAML session. This defines how long a user has to
   complete the authentication process, if `allow_unsolicited` is unset. The default is 15 minutes.
* `user_mapping_provider`: Using this option, an external module can be provided as a 
   custom solution to mapping attributes returned from a saml provider onto a matrix user. The 
   `user_mapping_provider` has the following attributes:
  * `module`: The custom module's class. 
  * `config`: Custom configuration values for the module. Use the values provided in the 
     example if you are using the built-in user_mapping_provider, or provide your own
     config values for a custom class if you are using one. This section will be passed as a Python
     dictionary to the module's `parse_config` method. The built-in provider takes the following two
     options:
      * `mxid_source_attribute`: The SAML attribute (after mapping via the attribute maps) to use
          to derive the Matrix ID from. It is 'uid' by default. Note: This used to be configured by the
          `saml2_config.mxid_source_attribute option`. If that is still defined, its value will be used instead.
      * `mxid_mapping`: The mapping system to use for mapping the saml attribute onto a
         matrix ID. Options include: `hexencode` (which maps unpermitted characters to '=xx')
         and `dotreplace` (which replaces unpermitted characters with '.').
         The default is `hexencode`. Note: This used to be configured by the
         `saml2_config.mxid_mapping option`. If that is still defined, its value will be used instead.
* `grandfathered_mxid_source_attribute`: In previous versions of synapse, the mapping from SAML attribute to
   MXID was always calculated dynamically rather than stored in a table. For backwards- compatibility, we will look for `user_ids`
   matching such a pattern before creating a new account. This setting controls the SAML attribute which will be used for this
   backwards-compatibility lookup. Typically it should be 'uid', but if the attribute maps are changed, it may be necessary to change it.
   The default is 'uid'. 
* `attribute_requirements`: It is possible to configure Synapse to only allow logins if SAML attributes
    match particular values. The requirements can be listed under
   `attribute_requirements` as shown in the example. All of the listed attributes must
    match for the login to be permitted.
* `idp_entityid`: If the metadata XML contains multiple IdP entities then the `idp_entityid`
   option must be set to the entity to redirect users to.
   Most deployments only have a single IdP entity and so should omit this option.
  

Once SAML support is enabled, a metadata file will be exposed at
`https://<server>:<port>/_synapse/client/saml2/metadata.xml`, which you may be able to
use to configure your SAML IdP with. Alternatively, you can manually configure
the IdP to use an ACS location of
`https://<server>:<port>/_synapse/client/saml2/authn_response`.

Example configuration:
```yaml
saml2_config:
  sp_config:
    metadata:
      local: ["saml2/idp.xml"]
      remote:
        - url: https://our_idp/metadata.xml
    accepted_time_diff: 3

    service:
      sp:
        allow_unsolicited: true

    # The examples below are just used to generate our metadata xml, and you
    # may well not need them, depending on your setup. Alternatively you
    # may need a whole lot more detail - see the pysaml2 docs!
    description: ["My awesome SP", "en"]
    name: ["Test SP", "en"]

    ui_info:
      display_name:
        - lang: en
          text: "Display Name is the descriptive name of your service."
      description:
        - lang: en
          text: "Description should be a short paragraph explaining the purpose of the service."
      information_url:
        - lang: en
          text: "https://example.com/terms-of-service"
      privacy_statement_url:
        - lang: en
          text: "https://example.com/privacy-policy"
      keywords:
        - lang: en
          text: ["Matrix", "Element"]
      logo:
        - lang: en
          text: "https://example.com/logo.svg"
          width: "200"
          height: "80"

    organization:
      name: Example com
      display_name:
        - ["Example co", "en"]
      url: "http://example.com"

    contact_person:
      - given_name: Bob
        sur_name: "the Sysadmin"
        email_address": ["admin@example.com"]
        contact_type": technical
        
  saml_session_lifetime: 5m
  
  user_mapping_provider:
    # Below options are intended for the built-in provider, they should be 
    # changed if using a custom module. 
    config:
      mxid_source_attribute: displayName
      mxid_mapping: dotreplace
  
  grandfathered_mxid_source_attribute: upn

  attribute_requirements:
    - attribute: userGroup
      value: "staff"
    - attribute: department
      value: "sales"

  idp_entityid: 'https://our_idp/entityid'
```
---
Config option: `oidc_providers`

List of OpenID Connect (OIDC) / OAuth 2.0 identity providers, for registration
and login. See [here](../../openid.md)
for information on how to configure these options.

For backwards compatibility, it is also possible to configure a single OIDC
provider via an `oidc_config` setting. This is now deprecated and admins are
advised to migrate to the `oidc_providers` format. (When doing that migration,
use `oidc` for the `idp_id` to ensure that existing users continue to be
recognised.)

Options for each entry include:
* `idp_id`: a unique identifier for this identity provider. Used internally
   by Synapse; should be a single word such as 'github'.
   Note that, if this is changed, users authenticating via that provider
   will no longer be recognised as the same user!
   (Use "oidc" here if you are migrating from an old `oidc_config` configuration.)

* `idp_name`: A user-facing name for this identity provider, which is used to
   offer the user a choice of login mechanisms.

* `idp_icon`: An optional icon for this identity provider, which is presented
   by clients and Synapse's own IdP picker page. If given, must be an
   MXC URI of the format mxc://<server-name>/<media-id>. (An easy way to
   obtain such an MXC URI is to upload an image to an (unencrypted) room
   and then copy the "url" from the source of the event.)

* `idp_brand`: An optional brand for this identity provider, allowing clients
   to style the login flow according to the identity provider in question.
   See the [spec](https://spec.matrix.org/latest/) for possible options here.

* `discover`: set to false to disable the use of the OIDC discovery mechanism
  to discover endpoints. Defaults to true.

* `issuer`: Required. The OIDC issuer. Used to validate tokens and (if discovery
   is enabled) to discover the provider's endpoints.

* `client_id`: Required. oauth2 client id to use.

* `client_secret`: oauth2 client secret to use. May be omitted if
  `client_secret_jwt_key` is given, or if `client_auth_method` is 'none'.

* `client_secret_jwt_key`: Alternative to client_secret: details of a key used
   to create a JSON Web Token to be used as an OAuth2 client secret. If
   given, must be a dictionary with the following properties:

  * `key`: a pem-encoded signing key. Must be a suitable key for the
    algorithm specified. Required unless `key_file` is given.

  * `key_file`: the path to file containing a pem-encoded signing key file.
     Required unless `key` is given.

  * `jwt_header`: a dictionary giving properties to include in the JWT
     header. Must include the key `alg`, giving the algorithm used to
     sign the JWT, such as "ES256", using the JWA identifiers in
     RFC7518.

  * `jwt_payload`: an optional dictionary giving properties to include in
    the JWT payload. Normally this should include an `iss` key.

* `client_auth_method`: auth method to use when exchanging the token. Valid
   values are `client_secret_basic` (default), `client_secret_post` and
   `none`.

* `scopes`: list of scopes to request. This should normally include the "openid"
   scope. Defaults to ["openid"].

* `authorization_endpoint`: the oauth2 authorization endpoint. Required if
   provider discovery is disabled.

* `token_endpoint`: the oauth2 token endpoint. Required if provider discovery is
   disabled.

* `userinfo_endpoint`: the OIDC userinfo endpoint. Required if discovery is
   disabled and the 'openid' scope is not requested.

* `jwks_uri`: URI where to fetch the JWKS. Required if discovery is disabled and
   the 'openid' scope is used.

* `skip_verification`: set to 'true' to skip metadata verification. Use this if
   you are connecting to a provider that is not OpenID Connect compliant.
   Defaults to false. Avoid this in production.

* `user_profile_method`: Whether to fetch the user profile from the userinfo
   endpoint, or to rely on the data returned in the id_token from the `token_endpoint`.
   Valid values are: `auto` or `userinfo_endpoint`.
   Defaults to `auto`, which uses the userinfo endpoint if `openid` is
   not included in `scopes`. Set to `userinfo_endpoint` to always use the
   userinfo endpoint.

* `allow_existing_users`: set to true to allow a user logging in via OIDC to
   match a pre-existing account instead of failing. This could be used if
   switching from password logins to OIDC. Defaults to false.

* `user_mapping_provider`: Configuration for how attributes returned from a OIDC
   provider are mapped onto a matrix user. This setting has the following
   sub-properties:

     * `module`: The class name of a custom mapping module. Default is
       `synapse.handlers.oidc.JinjaOidcMappingProvider`.
        See https://matrix-org.github.io/synapse/latest/sso_mapping_providers.html#openid-mapping-providers
        for information on implementing a custom mapping provider.

     * `config`: Configuration for the mapping provider module. This section will
        be passed as a Python dictionary to the user mapping provider
        module's `parse_config` method.

        For the default provider, the following settings are available:

       * subject_claim: name of the claim containing a unique identifier
         for the user. Defaults to 'sub', which OpenID Connect
         compliant providers should provide.

       * `localpart_template`: Jinja2 template for the localpart of the MXID.
          If this is not set, the user will be prompted to choose their
          own username (see the documentation for the `sso_auth_account_details.html` 
          template). This template can use the `localpart_from_email` filter.

       * `confirm_localpart`: Whether to prompt the user to validate (or
          change) the generated localpart (see the documentation for the
          'sso_auth_account_details.html' template), instead of
          registering the account right away.

       * `display_name_template`: Jinja2 template for the display name to set
          on first login. If unset, no displayname will be set.

       * `email_template`: Jinja2 template for the email address of the user.
          If unset, no email address will be added to the account.
                 
       * `extra_attributes`: a map of Jinja2 templates for extra attributes
          to send back to the client during login. Note that these are non-standard and clients will ignore them
          without modifications.

     When rendering, the Jinja2 templates are given a 'user' variable,
     which is set to the claims returned by the UserInfo Endpoint and/or
     in the ID Token.


It is possible to configure Synapse to only allow logins if certain attributes 
match particular values in the OIDC userinfo. The requirements can be listed under
`attribute_requirements` as shown here:
```yaml
attribute_requirements:
     - attribute: family_name
       value: "Stephensson"
     - attribute: groups
       value: "admin"
```
All of the listed attributes must match for the login to be permitted. Additional attributes can be added to
userinfo by expanding the `scopes` section of the OIDC config to retrieve
additional information from the OIDC provider.

If the OIDC claim is a list, then the attribute must match any value in the list.
Otherwise, it must exactly match the value of the claim. Using the example 
above, the `family_name` claim MUST be "Stephensson", but the `groups`
claim MUST contain "admin".

Example configuration:
```yaml
oidc_providers:
  # Generic example
  #
  - idp_id: my_idp
    idp_name: "My OpenID provider"
    idp_icon: "mxc://example.com/mediaid"
    discover: false
    issuer: "https://accounts.example.com/"
    client_id: "provided-by-your-issuer"
    client_secret: "provided-by-your-issuer"
    client_auth_method: client_secret_post
    scopes: ["openid", "profile"]
    authorization_endpoint: "https://accounts.example.com/oauth2/auth"
    token_endpoint: "https://accounts.example.com/oauth2/token"
    userinfo_endpoint: "https://accounts.example.com/userinfo"
    jwks_uri: "https://accounts.example.com/.well-known/jwks.json"
    skip_verification: true
    user_mapping_provider:
      config:
        subject_claim: "id"
        localpart_template: "{{ user.login }}"
        display_name_template: "{{ user.name }}"
        email_template: "{{ user.email }}"
    attribute_requirements:
      - attribute: userGroup
        value: "synapseUsers"
```
---
Config option: `cas_config`

Enable Central Authentication Service (CAS) for registration and login.
Has the following sub-options:
* `enabled`: Set this to true to enable authorization against a CAS server.
   Defaults to false.
* `server_url`: The URL of the CAS authorization endpoint.
* `displayname_attribute`: The attribute of the CAS response to use as the display name.
   If no name is given here, no displayname will be set.
* `required_attributes`:  It is possible to configure Synapse to only allow logins if CAS attributes
   match particular values. All of the keys given below must exist
   and the values must match the given value. Alternately if the given value
   is `None` then any value is allowed (the attribute just must exist).
   All of the listed attributes must match for the login to be permitted.

Example configuration:
```yaml
cas_config:
  enabled: true
  server_url: "https://cas-server.com"
  displayname_attribute: name
  required_attributes:
    userGroup: "staff"
    department: None
```
---
Config option: `sso`

Additional settings to use with single-sign on systems such as OpenID Connect,
SAML2 and CAS.

Server admins can configure custom templates for pages related to SSO. See 
[here](../../templates.md) for more information.

Options include:
* `client_whitelist`: A list of client URLs which are whitelisted so that the user does not
   have to confirm giving access to their account to the URL. Any client
   whose URL starts with an entry in the following list will not be subject
   to an additional confirmation step after the SSO login is completed.
   WARNING: An entry such as "https://my.client" is insecure, because it
   will also match "https://my.client.evil.site", exposing your users to
   phishing attacks from evil.site. To avoid this, include a slash after the
   hostname: "https://my.client/".
   The login fallback page (used by clients that don't natively support the
   required login flows) is whitelisted in addition to any URLs in this list.
   By default, this list contains only the login fallback page.
* `update_profile_information`: Use this setting to keep a user's profile fields in sync with information from
   the identity provider. Currently only syncing the displayname is supported. Fields 
   are checked on every SSO login, and are updated if necessary.
   Note that enabling this option will override user profile information,
   regardless of whether users have opted-out of syncing that
   information when first signing in. Defaults to false.


Example configuration:
```yaml
sso:
    client_whitelist:
      - https://riot.im/develop
      - https://my.custom.client/
    update_profile_information: true
```
---
Config option: `jwt_config`

JSON web token integration. The following settings can be used to make
Synapse JSON web tokens for authentication, instead of its internal
password database.

Each JSON Web Token needs to contain a "sub" (subject) claim, which is
used as the localpart of the mxid.

Additionally, the expiration time ("exp"), not before time ("nbf"),
and issued at ("iat") claims are validated if present.

Note that this is a non-standard login type and client support is
expected to be non-existent.

See [here](../../jwt.md) for more.

Additional sub-options for this setting include:
* `enabled`: Set to true to enable authorization using JSON web
   tokens. Defaults to false.
* `secret`: This is either the private shared secret or the public key used to
   decode the contents of the JSON web token. Required if `enabled` is set to true.
* `algorithm`: The algorithm used to sign the JSON web token. Supported algorithms are listed at
   https://pyjwt.readthedocs.io/en/latest/algorithms.html Required if `enabled` is set to true.
* `subject_claim`: Name of the claim containing a unique identifier for the user.
   Optional, defaults to `sub`.
* `issuer`: The issuer to validate the "iss" claim against. Optional. If provided the 
   "iss" claim will be required and validated for all JSON web tokens.
* `audiences`: A list of audiences to validate the "aud" claim against. Optional.
   If provided the "aud" claim will be required and validated for all JSON web tokens.
   Note that if the "aud" claim is included in a JSON web token then
   validation will fail without configuring audiences.

Example configuration:
```yaml
jwt_config:
    enabled: true 
    secret: "provided-by-your-issuer"
    algorithm: "provided-by-your-issuer"
    subject_claim: "name_of_claim"
    issuer: "provided-by-your-issuer"
    audiences:
        - "provided-by-your-issuer"
```
---
Config option: `password_config`

Use this setting to enable password-based logins. 

This setting has the following sub-options:
* `enabled`: Defaults to true.
* `localdb_enabled`: Set to false to disable authentication against the local password
   database. This is ignored if `enabled` is false, and is only useful
   if you have other `password_providers`. Defaults to true. 
* `pepper`: Set the value here to a secret random string for extra security. # Uncomment and change to a secret random string for extra security.
   DO NOT CHANGE THIS AFTER INITIAL SETUP!
* `policy`: Define and enforce a password policy, such as minimum lengths for passwords, etc. 
   Each parameter is optional. This is an implementation of MSC2000. Parameters are as follows:
   * `enabled`: Defaults to false. Set to true to enable.
   * `minimum_length`: Minimum accepted length for a password. Defaults to 0.
   * `require_digit`: Whether a password must contain at least one digit.
      Defaults to false.
   * `require_symbol`: Whether a password must contain at least one symbol.
      A symbol is any character that's not a number or a letter. Defaults to false.
   * `require_lowercase`: Whether a password must contain at least one lowercase letter.
      Defaults to false.
   * `require_uppercase`: Whether a password must contain at least one uppercase letter.
      Defaults to false.
      

Example configuration:
```yaml
password_config:
   enabled: false
   localdb_enabled: false
   pepper: "EVEN_MORE_SECRET"

   policy:
      enabled: true
      minimum_length: 15
      require_digit: true
      require_symbol: true
      require_lowercase: true
      require_uppercase: true
```
---
Config option: `ui_auth`

The amount of time to allow a user-interactive authentication session to be active.

This defaults to 0, meaning the user is queried for their credentials 
before every action, but this can be overridden to allow a single
validation to be re-used.  This weakens the protections afforded by
the user-interactive authentication process, by allowing for multiple
(and potentially different) operations to use the same validation session.

This is ignored for potentially "dangerous" operations (including
deactivating an account, modifying an account password, and
adding a 3PID).

Use the `session_timeout` sub-option here to change the time allowed for credential validation.

Example configuration:
```yaml
ui_auth:
    session_timeout: "15s"
```
---
Config option: `email`

Configuration for sending emails from Synapse.

Server admins can configure custom templates for email content. See
[here](../../templates.md) for more information.

This setting has the following sub-options:
* `smtp_host`: The hostname of the outgoing SMTP server to use. Defaults to 'localhost'.
* `smtp_port`: The port on the mail server for outgoing SMTP. Defaults to 25.
* `smtp_user` and `smtp_pass`: Username/password for authentication to the SMTP server. By default, no
   authentication is attempted.
* `require_transport_security`: Set to true to require TLS transport security for SMTP.
   By default, Synapse will connect over plain text, and will then switch to
   TLS via STARTTLS *if the SMTP server supports it*. If this option is set,
   Synapse will refuse to connect unless the server supports STARTTLS.
* `enable_tls`: By default, if the server supports TLS, it will be used, and the server
   must present a certificate that is valid for 'smtp_host'. If this option
   is set to false, TLS will not be used.
* `notif_from`: defines the "From" address to use when sending emails.
    It must be set if email sending is enabled. The placeholder '%(app)s' will be replaced by the application name,
    which is normally set in `app_name`, but may be overridden by the
    Matrix client application. Note that the placeholder must be written '%(app)s', including the
    trailing 's'.
* `app_name`: `app_name` defines the default value for '%(app)s' in `notif_from` and email
   subjects. It defaults to 'Matrix'.
* `enable_notifs`: Set to true to enable sending emails for messages that the user
   has missed. Disabled by default.
* `notif_for_new_users`: Set to false to disable automatic subscription to email
   notifications for new users. Enabled by default.
* `client_base_url`: Custom URL for client links within the email notifications. By default
   links will be based on "https://matrix.to". (This setting used to be called `riot_base_url`;
   the old name is still supported for backwards-compatibility but is now deprecated.)
* `validation_token_lifetime`: Configures the time that a validation email will expire after sending.
   Defaults to 1h.
* `invite_client_location`: The web client location to direct users to during an invite. This is passed
   to the identity server as the `org.matrix.web_client_location` key. Defaults
   to unset, giving no guidance to the identity server.
* `subjects`: Subjects to use when sending emails from Synapse. The placeholder '%(app)s' will
   be replaced with the value of the `app_name` setting, or by a value dictated by the Matrix client application.
   In addition, each subject can use the following placeholders: '%(person)s', which will be replaced by the displayname
   of the user(s) that sent the message(s), e.g. "Alice and Bob", and '%(room)s', which will be replaced by the name of the room the
   message(s) have been sent to, e.g. "My super room". In addition, emails related to account administration will
   can use the '%(server_name)s' placeholder, which will be replaced by the value of the
   `server_name` setting in your Synapse configuration.
   
   Here is a list of subjects for notification emails that can be set: 
     * `message_from_person_in_room`: Subject to use to notify about one message from one or more user(s) in a
        room which has a name. Defaults to "[%(app)s] You have a message on %(app)s from %(person)s in the %(room)s room..."
     * `message_from_person`: Subject to use to notify about one message from one or more user(s) in a
        room which doesn't have a name. Defaults to "[%(app)s] You have a message on %(app)s from %(person)s..."
     * `messages_from_person`: Subject to use to notify about multiple messages from one or more users in
        a room which doesn't have a name. Defaults to "[%(app)s] You have messages on %(app)s from %(person)s..."
     * `messages_in_room`: Subject to use to notify about multiple messages in a room which has a
        name. Defaults to "[%(app)s] You have messages on %(app)s in the %(room)s room..."
     * `messages_in_room_and_others`: Subject to use to notify about multiple messages in multiple rooms. 
        Defaults to "[%(app)s] You have messages on %(app)s in the %(room)s room and others..."
     * `messages_from_person_and_others`: Subject to use to notify about multiple messages from multiple persons in
        multiple rooms. This is similar to the setting above except it's used when
        the room in which the notification was triggered has no name. Defaults to 
        "[%(app)s] You have messages on %(app)s from %(person)s and others..."
     * `invite_from_person_to_room`: Subject to use to notify about an invite to a room which has a name. 
        Defaults to  "[%(app)s] %(person)s has invited you to join the %(room)s room on %(app)s..."
     * `invite_from_person`: Subject to use to notify about an invite to a room which doesn't have a
        name. Defaults to "[%(app)s] %(person)s has invited you to chat on %(app)s..."
     * `password_reset`: Subject to use when sending a password reset email. Defaults to "[%(server_name)s] Password reset"
     * `email_validation`: Subject to use when sending a verification email to assert an address's
        ownership. Defaults to "[%(server_name)s] Validate your email"

Example configuration:
```yaml
email:
  smtp_host: mail.server
  smtp_port: 587
  smtp_user: "exampleusername"
  smtp_pass: "examplepassword"
  require_transport_security: true
  enable_tls: false
  notif_from: "Your Friendly %(app)s homeserver <noreply@example.com>"
  app_name: my_branded_matrix_server
  enable_notifs: true
  notif_for_new_users: false
  client_base_url: "http://localhost/riot"
  validation_token_lifetime: 15m
  invite_client_location: https://app.element.io

  subjects:
    message_from_person_in_room: "[%(app)s] You have a message on %(app)s from %(person)s in the %(room)s room..."
    message_from_person: "[%(app)s] You have a message on %(app)s from %(person)s..."
    messages_from_person: "[%(app)s] You have messages on %(app)s from %(person)s..."
    messages_in_room: "[%(app)s] You have messages on %(app)s in the %(room)s room..."
    messages_in_room_and_others: "[%(app)s] You have messages on %(app)s in the %(room)s room and others..."
    messages_from_person_and_others: "[%(app)s] You have messages on %(app)s from %(person)s and others..."
    invite_from_person_to_room: "[%(app)s] %(person)s has invited you to join the %(room)s room on %(app)s..."
    invite_from_person: "[%(app)s] %(person)s has invited you to chat on %(app)s..."
    password_reset: "[%(server_name)s] Password reset"
    email_validation: "[%(server_name)s] Validate your email"
```
---
## Push ##
Configuration settings related to push notifications

---
Config option: `push`

This setting defines options for push notifications. 

This option has a number of sub-options. They are as follows:
* `include_content`: Clients requesting push notifications can either have the body of
   the message sent in the notification poke along with other details
   like the sender, or just the event ID and room ID (`event_id_only`).
   If clients choose the to have the body sent, this option controls whether the
   notification request includes the content of the event (other details
   like the sender are still included). If `event_id_only` is enabled, it
   has no effect.
   For modern android devices the notification content will still appear
   because it is loaded by the app. iPhone, however will send a
   notification saying only that a message arrived and who it came from.
   Defaults to true. Set to false to only include the event ID and room ID in push notification payloads.
* `group_unread_count_by_room: false`: When a push notification is received, an unread count is also sent.
   This number can either be calculated as the number of unread messages  for the user, or the number of *rooms* the 
   user has unread messages in. Defaults to true, meaning push clients will see the number of
   rooms with unread messages in them. Set to false to instead send the number
   of unread messages.

Example configuration:
```yaml
push:
  include_content: false
  group_unread_count_by_room: false
```
---
## Rooms ##
Config options relating to rooms.

---
Config option: `encryption_enabled_by_default`

Controls whether locally-created rooms should be end-to-end encrypted by
default.

Possible options are "all", "invite", and "off". They are defined as:

* "all": any locally-created room
* "invite": any room created with the `private_chat` or `trusted_private_chat`
   room creation presets
* "off": this option will take no effect

The default value is "off".

Note that this option will only affect rooms created after it is set. It
will also not affect rooms created by other servers.

Example configuration:
```yaml
encryption_enabled_by_default_for_room_type: invite
```
---
Config option: `enable_group_creation`

Set to true to allow non-server-admin users to create groups on this server

Example configuration:
```yaml
enable_group_creation: true
```
---
Config option: `group_creation_prefix`

If enabled/present, non-server admins can only create groups with local parts
starting with this prefix.

Example configuration:
```yaml
group_creation_prefix: "unofficial_"
```
---
Config option: `user_directory`

This setting defines options related to the user directory. 

This option has the following sub-options:
* `enabled`:  Defines whether users can search the user directory. If false then
   empty responses are returned to all queries. Defaults to true.
* `search_all_users`: Defines whether to search all users visible to your HS when searching
   the user directory. If false, search results will only contain users
    visible in public rooms and users sharing a room with the requester.
    Defaults to false.
    NB. If you set this to true, and the last time the user_directory search
    indexes were (re)built was before Synapse 1.44, you'll have to
    rebuild the indexes in order to search through all known users.
    These indexes are built the first time Synapse starts; admins can
    manually trigger a rebuild via API following the instructions at
         https://matrix-org.github.io/synapse/latest/usage/administration/admin_api/background_updates.html#run
    Set to true to return search results containing all known users, even if that
    user does not share a room with the requester.
* `prefer_local_users`: Defines whether to prefer local users in search query results.
   If set to true, local users are more likely to appear above remote users when searching the 
   user directory. Defaults to false.

Example configuration:
```yaml
user_directory:
    enabled: false
    search_all_users: true
    prefer_local_users: true
```
---
Config option: `user_consent`

For detailed instructions on user consent configuration, see [here](../../consent_tracking.md).

Parts of this section are required if enabling the `consent` resource under
`listeners`, in particular `template_dir` and `version`. # TODO: link `listeners`

* `template_dir`: gives the location of the templates for the HTML forms.
  This directory should contain one subdirectory per language (eg, `en`, `fr`),
  and each language directory should contain the policy document (named as
  <version>.html) and a success page (success.html).

* `version`: specifies the 'current' version of the policy document. It defines
   the version to be served by the consent resource if there is no 'v'
   parameter.

* `server_notice_content`: if enabled, will send a user a "Server Notice"
   asking them to consent to the privacy policy. The `server_notices` section ##TODO: link
   must also be configured for this to work. Notices will *not* be sent to
   guest users unless `send_server_notice_to_guests` is set to true.

* `block_events_error`, if set, will block any attempts to send events
   until the user consents to the privacy policy. The value of the setting is
   used as the text of the error.

* `require_at_registration`, if enabled, will add a step to the registration
   process, similar to how captcha works. Users will be required to accept the
   policy before their account is created.

* `policy_name` is the display name of the policy users will see when registering
   for an account. Has no effect unless `require_at_registration` is enabled.
   Defaults to "Privacy Policy".

Example configuration:
```yaml
user_consent:
  template_dir: res/templates/privacy
  version: 1.0
  server_notice_content:
    msgtype: m.text
    body: >-
      To continue using this homeserver you must review and agree to the
      terms and conditions at %(consent_uri)s
  send_server_notice_to_guests: true
  block_events_error: >-
    To continue using this homeserver you must review and agree to the
    terms and conditions at %(consent_uri)s
  require_at_registration: false
  policy_name: Privacy Policy
```
---
Config option: `stats`

Settings for local room and user statistics collection. See [here](../../room_and_user_statistics.md)
for more. 

* `enabled`: Set to false to disable room and user statistics. Note that doing
   so may cause certain features (such as the room directory) not to work
   correctly. Defaults to true. 

Example configuration:
```yaml
stats:  
  enabled: false
```
---
Config option: `server_notices`

Use this setting to enable a room which can be used to send notices
from the server to users. It is a special room which users cannot leave; notices
in the room come from a special "notices" user id.

If you use this setting, you *must* define the `system_mxid_localpart`
sub-setting, which defines the id of the user which will be used to send the
notices.

Sub-options for this setting include:
* `system_mxid_display_name`: set the display name of the "notices" user
* `system_mxid_avatar_url`: set the avatar for the "notices" user
* `room_name`: set the room name of the server notices room

Example configuration:
```yaml
server_notices:
  system_mxid_localpart: notices
  system_mxid_display_name: "Server Notices"
  system_mxid_avatar_url: "mxc://server.com/oumMVlgDnLYFaPVkExemNVVZ"
  room_name: "Server Notices"
```
---
Config option: `enable_room_list_search`

Set to false to disable searching the public room list. When disabled
blocks searching local and remote room lists for local and remote
users by always returning an empty list for all queries. Defaults to true. 

Example configuration:
```yaml
enable_room_list_search: false
```
---
Config option: `alias_creation`

The `alias_creation` option controls who is allowed to create aliases
on this server.

The format of this option is a list of rules that contain globs that
match against user_id, room_id and the new alias (fully qualified with
server name). The action in the first rule that matches is taken,
which can currently either be "allow" or "deny".

Missing user_id/room_id/alias fields default to "*".

If no rules match the request is denied. An empty list means no one
can create aliases.

Options for the rules include:
* `user_id`: Matches against the creator of the alias. Defaults to "*".
* `alias`: Matches against the alias being created. Defaults to "*".
* `room_id`: Matches against the room ID the alias is being pointed at. Defaults to "*"
* `action`: Whether to "allow" or "deny" the request if the rule matches. Defaults to allow. 

Example configuration:
```yaml
alias_creation_rules:
  - user_id: "bad_user"
    alias: "spammy_alias"
    room_id: "*"
    action: deny
```
---
Config options: `room_list_publication_rules`

The `room_list_publication_rules` option controls who can publish and
which rooms can be published in the public room list.

The format of this option is the same as that for
`alias_creation_rules`.

If the room has one or more aliases associated with it, only one of
the aliases needs to match the alias rule. If there are no aliases
then only rules with `alias: *` match.

If no rules match the request is denied. An empty list means no one
can publish rooms.

Options for the rules include:
* `user_id`: Matches against the creator of the alias. Defaults to "*".
* `alias`: Matches against any current local or canonical aliases associated with the room. Defaults to "*".
* `room_id`: Matches against the room ID being published. Defaults to "*".
* `action`: Whether to "allow" or "deny" the request if the rule matches. Defaults to allow. 

Example configuration:
```yaml
room_list_publication_rules:
  - user_id: "*"
    alias: "*"
    room_id: "*"
    action: allow
```

---
Config option: `default_power_level_content_override`

The `default_power_level_content_override` option controls the default power
levels for rooms.

Useful if you know that your users need special permissions in rooms
that they create (e.g. to send particular types of state events without
needing an elevated power level).  This takes the same shape as the
`power_level_content_override` parameter in the /createRoom API, but
is applied before that parameter.

Note that each key provided inside a preset (for example `events` in the example
below) will overwrite all existing defaults inside that key. So in the example
below, newly-created private_chat rooms will have no rules for any event types
except `com.example.foo`.

Example configuration:
```yaml
default_power_level_content_override:
   private_chat: { "events": { "com.example.foo" : 0 } }
   trusted_private_chat: null
   public_chat: null
```

---
## Opentracing ##
Configuration options related to Opentracing support.

---
Config option: `opentracing`

These settings enable and configure opentracing, which implements distributed tracing.
This allows you to observe the causal chains of events across servers
including requests, key lookups etc., across any server running
synapse or any other services which support opentracing
(specifically those implemented with Jaeger).

Sub-options include:
* `enabled`: whether tracing is enabled. Set to true to enable. Disabled by default.
* `homeserver_whitelist`: The list of homeservers we wish to send and receive span contexts and span baggage.
   See [here](../../opentracing.md) for more. 
   This is a list of regexes which are matched against the `server_name` of the homeserver.
   By default, it is empty, so no servers are matched.
* `force_tracing_for_users`: # A list of the matrix IDs of users whose requests will always be traced,
   even if the tracing system would otherwise drop the traces due to probabilistic sampling.
    By default, the list is empty.
* `jaeger_config`: Jaeger can be configured to sample traces at different rates.
   All configuration options provided by Jaeger can be set here. Jaeger's configuration is 
   mostly related to trace sampling which is documented [here](https://www.jaegertracing.io/docs/latest/sampling/).

Example configuration:
```yaml
opentracing:
    enabled: true
    homeserver_whitelist:
      - ".*"
    force_tracing_for_users:
      - "@user1:server_name"
      - "@user2:server_name"

    jaeger_config:
      sampler:
        type: const
        param: 1
      logging:
        false
```
---
## Workers ##
Configuration options related to workers.

---
Config option: `send_federation`

Controls sending of outbound federation transactions on the main process.
Set to false if using a federation sender worker. Defaults to true. 

Example configuration:
```yaml
send_federation: false
```
---
Config option: `federation_sender_instances`

It is possible to run multiple federation sender workers, in which case the
work is balanced across them. Use this setting to list the senders. 

This configuration setting must be shared between all federation sender workers, and if
changed all federation sender workers must be stopped at the same time and then
started, to ensure that all instances are running with the same config (otherwise
events may be dropped). 

Example configuration:
```yaml
federation_sender_instances:
  - federation_sender1
```
---
Config option: `instance_map`

When using workers this should be a map from worker name to the
HTTP replication listener of the worker, if configured. 

Example configuration:
```yaml
instance_map:
  worker1:
    host: localhost
    port: 8034
```
---
Config option: `stream_writers`

Experimental: When using workers you can define which workers should
handle event persistence and typing notifications. Any worker
specified here must also be in the `instance_map`.

Example configuration:
```yaml
stream_writers:
  events: worker1
  typing: worker1
```
---
Config option: `run_background_tasks_on`

The worker that is used to run background tasks (e.g. cleaning up expired
data). If not provided this defaults to the main process.

Example configuration:
```yaml
run_background_tasks_on: worker1
```
---
Config option: `worker_replication_secret`

A shared secret used by the replication APIs to authenticate HTTP requests
from workers.

By default this is unused and traffic is not authenticated.

Example configuration:
```yaml
worker_replication_secret: "secret_secret"
```
Config option: `redis`

Configuration for Redis when using workers. This *must* be enabled when
using workers (unless using old style direct TCP configuration).
This setting has the following sub-options:
* `enabled`: whether to use Redis support. Defaults to false. 
* `host` and `port`: Optional host and port to use to connect to redis. Defaults to
   localhost and 6379
* `password`: Optional password if configured on the Redis instance.

Example configuration:
```yaml
redis:
  enabled: true
  host: localhost
  port: 6379
  password: <secret_password>
```
## Background Updates ##
Configuration settings related to background updates. 

---
Config option: `background_updates`

Background updates are database updates that are run in the background in batches.
The duration, minimum batch size, default batch size, whether to sleep between batches and if so, how long to
sleep can all be configured. This is helpful to speed up or slow down the updates.
This setting has the following sub-options:
* `background_update_duration_ms`: How long in milliseconds to run a batch of background updates for. Defaults to 100. 
   Set a different time to change the default.
* `sleep_enabled`: Whether to sleep between updates. Defaults to true. Set to false to change the default.
* `sleep_duration_ms`: If sleeping between updates, how long in milliseconds to sleep for. Defaults to 1000.
   Set a duration to change the default.
* `min_batch_size`: Minimum size a batch of background updates can be. Must be greater than 0. Defaults to 1.
   Set a size to change the default.
* `default_batch_size`: The batch size to use for the first iteration of a new background update. The default is 100.
   Set a size to change the default.

Example configuration: 
```yaml
background_updates:
    background_update_duration_ms: 500
    sleep_enabled: false
    sleep_duration_ms: 300
    min_batch_size: 10
    default_batch_size: 50
```