Fully read markers

The history for a given room may be split into three sections: messages the user has read (or indicated they aren’t interested in them), messages the user might have read some but not others, and messages the user hasn’t seen yet. The “fully read marker” (also known as a “read marker”) marks the last event of the first section, whereas the user’s read receipt marks the last event of the second section.

Events

The user’s fully read marker is kept as an event in the room’s account data. The event may be read to determine the user’s current fully read marker location in the room, and just like other account data events the event will be pushed down the event stream when updated.

The fully read marker is kept under an m.fully_read event. If the event does not exist on the user’s account data, the fully read marker should be considered to be the user’s read receipt location.

`m.fully_read`

The current location of the user’s read marker in a room. This event appears in the user’s room account data for the room the marker is applicable for.

Event type:	Message event

Content

Name	Type	Description
`event_id`	`string`	Required: The event the user’s read marker is located at in the room.

Examples

{
  "content": {
    "event_id": "$someplace:example.org"
  },
  "room_id": "!somewhere:example.org",
  "type": "m.fully_read"
}

Client behaviour

The client cannot update fully read markers by directly modifying the m.fully_read account data event. Instead, the client must make use of the read markers API to change the values.

The read markers API can additionally update the user’s read receipt (m.read) location in the same operation as setting the fully read marker location. This is because read receipts and read markers are commonly updated at the same time, and therefore the client might wish to save an extra HTTP call. Providing an m.read location performs the same task as a request to /receipt/m.read/$event:example.org.

POST /_matrix/client/r0/rooms/{roomId}/read_markers

Sets the position of the read marker for a given room, and optionally the read receipt’s location.

Rate-limited:	Yes
Requires authentication:	Yes

Request

Request parameters

path parameters
Name	Type	Description
`roomId`	`string`	Required: The room ID to set the read marker in for the user.

Request body

Name	Type	Description
`m.fully_read`	`string`	Required: The event ID the read marker should be located at. The event MUST belong to the room.
`m.read`	`string`	The event ID to set the read receipt location at. This is equivalent to calling `/receipt/m.read/$elsewhere:example.org` and is provided here to save that extra call.

Request body example

{
  "m.fully_read": "$somewhere:example.org",
  "m.read": "$elsewhere:example.org"
}

Responses

Status	Description
`200`	The read marker, and read receipt if provided, have been updated.
`429`	This request was rate-limited.

429 response

Name	Type	Description
`errcode`	`string`	Required: The M_LIMIT_EXCEEDED error code
`error`	`string`	A human-readable error message.
`retry_after_ms`	`integer`	The amount of time in milliseconds the client should wait before trying the request again.

{
  "errcode": "M_LIMIT_EXCEEDED",
  "error": "Too many requests",
  "retry_after_ms": 2000
}

Server behaviour

The server MUST prevent clients from setting m.fully_read directly in room account data. The server must additionally ensure that it treats the presence of m.read in the /read_markers request the same as how it would for a request to /receipt/m.read/$event:example.org.

Upon updating the m.fully_read event due to a request to /read_markers, the server MUST send the updated account data event through to the client via the event stream (eg: /sync), provided any applicable filters are also satisfied.