1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py

index 539c353528..0d3ae1a43d 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -227,7 +227,7 @@ class BucketCollector(object):
                     break
 
         for i in self.buckets:
-            res.append([i, buckets.get(i, 0)])
+            res.append([str(i), buckets.get(i, 0)])
 
         res.append(["+Inf", sum(data.values())])