API object type


A group object contains information about a private channel created before March 2021. The private channel's ID will begin with G, as private channels were once known as "private groups." Conversation objects contain the information for private channels created after March 2021 (those with IDs that begin with C).

        "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 no-one 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 Indicates the name of the private channel.
is_group boolean Indicates if 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 Indicates if 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 is the Unix timestamp for the last message the calling user has read in this channel.
  • unread_count is a full count of visible messages that the calling user has yet to read.
  • unread_count_display is 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 is the latest message in the channel.