diff --git a/synapse/handlers/account.py b/synapse/handlers/account.py
new file mode 100644
index 0000000000..f8cfe9f6de
--- /dev/null
+++ b/synapse/handlers/account.py
@@ -0,0 +1,144 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import TYPE_CHECKING, Dict, List, Tuple
+
+from synapse.api.errors import Codes, SynapseError
+from synapse.types import JsonDict, UserID
+
+if TYPE_CHECKING:
+ from synapse.server import HomeServer
+
+
+class AccountHandler:
+ def __init__(self, hs: "HomeServer"):
+ self._store = hs.get_datastore()
+ self._is_mine = hs.is_mine
+ self._federation_client = hs.get_federation_client()
+
+ async def get_account_statuses(
+ self,
+ user_ids: List[str],
+ allow_remote: bool,
+ ) -> Tuple[JsonDict, List[str]]:
+ """Get account statuses for a list of user IDs.
+
+ If one or more account(s) belong to remote homeservers, retrieve their status(es)
+ over federation if allowed.
+
+ Args:
+ user_ids: The list of accounts to retrieve the status of.
+ allow_remote: Whether to try to retrieve the status of remote accounts, if
+ any.
+
+ Returns:
+ The account statuses as well as the list of users whose statuses could not be
+ retrieved.
+
+ Raises:
+ SynapseError if a required parameter is missing or malformed, or if one of
+ the accounts isn't local to this homeserver and allow_remote is False.
+ """
+ statuses = {}
+ failures = []
+ remote_users: List[UserID] = []
+
+ for raw_user_id in user_ids:
+ try:
+ user_id = UserID.from_string(raw_user_id)
+ except SynapseError:
+ raise SynapseError(
+ 400,
+ f"Not a valid Matrix user ID: {raw_user_id}",
+ Codes.INVALID_PARAM,
+ )
+
+ if self._is_mine(user_id):
+ status = await self._get_local_account_status(user_id)
+ statuses[user_id.to_string()] = status
+ else:
+ if not allow_remote:
+ raise SynapseError(
+ 400,
+ f"Not a local user: {raw_user_id}",
+ Codes.INVALID_PARAM,
+ )
+
+ remote_users.append(user_id)
+
+ if allow_remote and len(remote_users) > 0:
+ remote_statuses, remote_failures = await self._get_remote_account_statuses(
+ remote_users,
+ )
+
+ statuses.update(remote_statuses)
+ failures += remote_failures
+
+ return statuses, failures
+
+ async def _get_local_account_status(self, user_id: UserID) -> JsonDict:
+ """Retrieve the status of a local account.
+
+ Args:
+ user_id: The account to retrieve the status of.
+
+ Returns:
+ The account's status.
+ """
+ status = {"exists": False}
+
+ userinfo = await self._store.get_userinfo_by_id(user_id.to_string())
+
+ if userinfo is not None:
+ status = {
+ "exists": True,
+ "deactivated": userinfo.is_deactivated,
+ }
+
+ return status
+
+ async def _get_remote_account_statuses(
+ self, remote_users: List[UserID]
+ ) -> Tuple[JsonDict, List[str]]:
+ """Send out federation requests to retrieve the statuses of remote accounts.
+
+ Args:
+ remote_users: The accounts to retrieve the statuses of.
+
+ Returns:
+ The statuses of the accounts, and a list of accounts for which no status
+ could be retrieved.
+ """
+ # Group remote users by destination, so we only send one request per remote
+ # homeserver.
+ by_destination: Dict[str, List[str]] = {}
+ for user in remote_users:
+ if user.domain not in by_destination:
+ by_destination[user.domain] = []
+
+ by_destination[user.domain].append(user.to_string())
+
+ # Retrieve the statuses and failures for remote accounts.
+ final_statuses: JsonDict = {}
+ final_failures: List[str] = []
+ for destination, users in by_destination.items():
+ statuses, failures = await self._federation_client.get_account_status(
+ destination,
+ users,
+ )
+
+ final_statuses.update(statuses)
+ final_failures += failures
+
+ return final_statuses, final_failures
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