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Message retention policies#

Message retention policies exist at a room level, follow the semantics described in MSC1763, and allow server and room admins to configure how long messages should be kept in a homeserver's database before being purged from it.


Please note that, as this feature isn't part of the Matrix specification yet, this implementation is to be considered as experimental.

A message retention policy is mainly defined by its max_lifetime parameter, which defines how long a message can be kept around after it was sent to the room. If a room doesn't have a message retention policy, and there's no default one for a given server, then no message sent in that room is ever purged on that server.

MSC1763 also specifies semantics for a min_lifetime parameter which defines the amount of time after which an event can get purged (after it was sent to the room), but Synapse doesn't currently support it beyond registering it.

Both max_lifetime and min_lifetime are optional parameters.


Note that message retention policies don't apply to state events.

more information about Message retention policies can find here.

Lifetime limits on

Our current instance lifetime limits are:

  allowed_lifetime_min: 30m
  allowed_lifetime_max: 10y

Room configuration#

To configure a room's message retention policy, a room's admin or moderator needs to send a state event in that room with the type and the following content:

  • Type /devtools.
  • Select "Explore room state" -> "Send custom state event"
  • Set event type to ("State Key" can be left blank)
    "max_lifetime": ...

Press Send

In this event's content, the max_lifetime parameter has the same meaning as previously described, and needs to be expressed in milliseconds. The event's content can also include a min_lifetime parameter, which has the same meaning and limited support as previously described.


Note that over every server in the room, only the ones with support for message retention policies will actually remove expired events. This support is currently not enabled by default in Synapse.