rtm.start

This method begins a Real Time Messaging API session and reserves your application a specific URL with which to connect via websocket.

It's user-centric and team-centric: your app connects as a specific user or bot user on a specific team. Many apps will find the Events API's subscription model more scalable when working against multiple teams.

This method also returns a smorgasbord of data about the team, its channels, and members. Some times more information than can be provided in a timely or helpful manner.

Please use rtm.connect instead, especially when connecting on behalf of an Enterprise Grid customer.

Consult the RTM API documentation for full details on using the RTM API. You'll also find our changelog entry useful.

The members array found in this and other methods will begin automatically truncating at 1,500 and eventually fewer results beginning December 1, 2017. As of March, 2018 the cap is 500. Please Use conversations.members to manage memberships instead. Read on to learn more.

New Slack apps may not use any Real Time Messaging API method. Create a classic app and use the V1 Oauth flow to use RTM.

For most applications, Socket Mode is a better way to communicate with Slack.

Note that setting no_latest=1 will automatically set no_unreads=1.

This method returns lots of data about the current state of a team, along with a WebSocket Message Server URL:

{
    "ok": true,
    "url": "wss:\/\/wss-primary.slack.com\/websocket\/7I5yBpcvk",

    "self": {
        "id": "U023BECGF",
        "name": "bobby",
        "prefs": {
            ...
        },
        "created": 1402463766,
        "manual_presence": "active"
    },
    "team": {
        "id": "T024BE7LD",
        "name": "Example Team",
        "email_domain": "",
        "domain": "example",
        "icon": {
            ...
        },
        "msg_edit_window_mins": -1,
        "over_storage_limit": false
        "prefs": {
            ...
        },
        "plan": "std"
    },
    "users": [ ... ],

    "channels": [ ... ],
    "groups": [ ... ],
    "mpims": [ ... ],
    "ims": [ ... ],

    "bots": [ ... ],
}

The url property contains a WebSocket Message Server URL. Connecting to this URL will initiate a Real Time Messaging session. These URLs are only valid for 30 seconds, so connect quickly!

The self property contains details on the authenticated user.

The team property contains details on the authenticated user's team. If a team has not yet set a custom icon, the value of team.icon.image_default will be true.

The users property contains a list of user objects, one for every member of the team. presence is no longer included for users. The list of users may truncate on especially long teams. Use Web API methods to retrieve information about users instead.

The channels property is a list of channel objects, one for every channel visible to the authenticated user. For regular or administrator accounts this list will include every team channel. The is_member property indicates if the user is a member of this channel. If true then the channel object will also include the topic, purpose, member list and read-state related information. The latest, unread_count, and unread_count_display attributes have been removed from this method's response. See this changelog entry.

The groups property is a list of group objects, one for every group the authenticated user is in.

The mpims property is a list of mpims objects, one for every group the authenticated user is in. MPIMs are only returned to the client if mpim_aware is set when calling rtm.start. Otherwise, mpims are emulated using the groups API.

The ims property is a list of IM objects, one for every direct message channel visible to the authenticated user.

The bots property gives details of the integrations set up on this team.