Monthly Active Users

Synapse can be configured to record the number of monthly active users (also referred to as MAU) on a given homeserver. For clarity's sake, MAU only tracks local users.

Please note that the metrics recorded by the Homeserver Usage Stats are calculated differently. The monthly_active_users from the usage stats does not take into account any of the rules below, and counts any users who have made a request to the homeserver in the last 30 days.

See the configuration manual for details on how to configure MAU.

Calculating active users

Individual user activity is measured in active days. If a user performs an action, the exact time of that action is then recorded. When calculating the MAU figure, any users with a recorded action in the last 30 days are considered part of the cohort. Days are measured as a rolling window from the current system time to 30 days ago.

So for example, if Synapse were to calculate the active users on the 15th July at 13:25, it would include any activity from 15th June 13:25 onwards.

A user is never considered active if they are either:

• Part of the trial day cohort (described below)
• Owned by an application service.
  • Note: This only covers users that are part of an application service namespaces.users registration. The namespace must also be marked as exclusive.

Otherwise, any request to Synapse will mark the user as active. Please note that registration will not mark a user as active unless they register with a 3pid that is included in the config field mau_limits_reserved_threepids.

The Prometheus metric for MAU is refreshed every 5 minutes.

Once an hour, Synapse checks to see if any users are inactive (with only activity timestamps later than 30 days). These users are removed from the active users cohort. If they then become active, they are immediately restored to the cohort.

It is important to note that deactivated users are not immediately removed from the pool of active users, but as these users won't perform actions they will eventually be removed from the cohort.

Trial days

If the config option mau_trial_days is set, a user must have been active this many days after registration to be active. A user is in the trial period if their registration timestamp (also known as the creation_ts) is less than mau_trial_days old.

As an example, if mau_trial_days is set to 3 and a user is active after 3 days (72 hours from registration time) then they will be counted as active.

The mau_appservice_trial_days config further extends this rule by applying different durations depending on the appservice_id of the user. Users registered by an application service will be recorded with an appservice_id matching the id key in the registration file for that service.

Limiting usage of the homeserver when the maximum MAU is reached

If both config options limit_usage_by_mau and max_mau_value is set, and the current MAU value exceeds the maximum value, the homeserver will begin to block some actions.

Individual users matching any of the below criteria never have their actions blocked:

• Considered part of the cohort of MAU users.
• Considered part of the trial period.
• Registered as a support user.
• Application service users if track_appservice_user_ips is NOT set.

Please not that server admins are not exempt from blocking.

The following actions are blocked when the MAU limit is exceeded:

• Logging in
• Sending events
• Creating rooms
• Syncing

Registration is also blocked for all new signups unless the user is registering with a threepid included in the mau_limits_reserved_threepids config value.

When a request is blocked, the response will have the errcode M_RESOURCE_LIMIT_EXCEEDED.

Metrics

Synapse records several different prometheus metrics for MAU.

synapse_admin_mau_current records the current MAU figure for native (non-application-service) users.

synapse_admin_mau_max records the maximum MAU as dictated by the max_mau_value config value.

synapse_admin_mau_current_mau_by_service records the current MAU including application service users. The label app_service can be used to filter by a specific service ID. This also includes non-application-service users under app_service=native .

synapse_admin_mau_registered_reserved_users records the number of users specified in mau_limits_reserved_threepids which have registered accounts on the homeserver.