group type

A group object contains information about a private channel. Private channels were once known as "private groups." Consider a group object the same thing as a private channel object.

{
    "id": "G024BE91L",
    "name": "secretplans",
    "is_group": "true",
    "created": 1360782804,
    "creator": "U024BE7LH",
    "is_archived": false,
    "is_mpim": false,
    "members": [
        "U024BE7LH"
    ],
    "topic": {
        "value": "Secret plans on hold",
        "creator": "U024BE7LV",
        "last_set": 1369677212
    },
    "purpose": {
        "value": "Discuss secret plans that no-one else should know",
        "creator": "U024BE7LH",
        "last_set": 1360782804
    },

    "last_read": "1401383885.000061",
    "latest": { … }
    "unread_count": 0,
    "unread_count_display": 0

},

The name parameter indicates the name of the private channel.

creator is the user ID of the member that created this private channel. created is a unix timestamp.

is_archived will be true if the private channel is archived.

members is 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.

mpims is a boolean that indicated if a multiparty im (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.

topic and purpose provide information about the private channel topic and purpose.

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 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.