API object type


A group object contains information about a private channel that was created before March 2021. The private channel's ID will begin with G, as private channels were previously known as "private groups."

For information about private channels created after March 2021 (those with IDs that begin with C the same as public channels do), refer to conversation objects. The Conversations API will tell you whether a conversation is private or not with the is_private boolean field.

An example response is below:

        "id": "G123456",
        "name": "secretplans",
        "is_group": "true",
        "created": 1360782804,
        "creator": "U123456",
        "is_archived": false,
        "is_mpim": false,
        "members": [
        "topic": {
            "value": "Secret plans on hold",
            "creator": "U123456",
            "last_set": 1369677212
        "purpose": {
            "value": "Discuss secret plans that nobody else should know",
            "creator": "U123456",
            "last_set": 1360782804
        "last_read": "1401383885.000061",
        "latest": { … },
        "unread_count": 0,
        "unread_count_display": 0

Field Type Description
id string The ID of the private channel.
name string The name of the private channel.
is_group boolean Whether this object is a group.
created Unix timestamp When the conversation was created.
creator string The user ID of the member that created this private channel.
is_archived boolean true if the private channel is archived.
is_mpim boolean Whether a multiparty instant message (mpim) is being emulated as a private channel. For compatibility with older clients, mpims can appear as private channels unless rtm.start is called with mpim_aware=1.
members array A list of user IDs for all users in this private channel. This includes any disabled accounts that were in this private channel when they were disabled.
topic object The topic of the group.
purpose object The purpose of the group.

Some API methods (such as groups.create) will include extra state information for channels when the calling user is a member:

  • last_read: the Unix timestamp for the last message the calling user has read in this channel.
  • unread_count: a full count of visible messages that the calling user has yet to read.
  • unread_count_display: a count of messages that the calling user has yet to read that matter to them (this means it excludes things like join/leave messages).
  • latest: the latest message in the channel.