For AI agents: markdown of this page — /docs-content-en/chats/members/membership.md documentation index — /llms.txt

Membership check

GET /v1/chats/:dialogId/users/membership

Checks which of the listed users are members of the chat — the v2 messenger method im.v2.Chat.Member.checkMembership. One request answers the question for a list of up to 50 users at once: for example, before inviting users to the chat or mentioning them.

Parameters

Parameter Type Required Default Description
dialogId (path) string yes — Dialog ID: chatXXX for a group chat, a user ID for a direct dialog, or the me alias
userIds (query) string yes — From 1 to 50 Bitrix24 user IDs separated by commas, for example 7,12. Each ID is a positive integer without spaces or leading zeros. A repeated ID is allowed and counts toward the limit of 50

Any other parameter or a repeated parameter is rejected with 400 INVALID_PARAMS.

Examples

curl — personal key

Terminal 
curl "https://vibecode.bitrix24.com/v1/chats/chat123/users/membership?userIds=7,12" \
  -H "X-Api-Key: YOUR_API_KEY"

curl — OAuth application

Terminal 
curl "https://vibecode.bitrix24.com/v1/chats/chat123/users/membership?userIds=7,12" \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN"

JavaScript — personal key

javascript 
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/chat123/users/membership?userIds=7,12', {
  headers: { 'X-Api-Key': 'YOUR_API_KEY' },
})

const { data } = await res.json()
console.log('Not in the chat:', data.usersNotInChat)

JavaScript — OAuth application

javascript 
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/chat123/users/membership?userIds=7,12', {
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
  },
})

const { data } = await res.json()

Response fields

Field Type Description
success boolean Always true on success
data.usersInChat array IDs of the requested users who are chat members
data.usersNotInChat array IDs of the requested users who are not chat members
data.users array Brief profiles of all requested users
data.users[].id number User ID
data.users[].name string Full name
data.users[].avatar string Avatar URL. An empty string when no avatar is set
data.users[].color string Avatar color in hexadecimal format
data.users[].type string User type: user, extranet, bot and others

Response example

JSON 
{
  "success": true,
  "data": {
    "usersInChat": [7],
    "usersNotInChat": [12],
    "users": [
      { "id": 7, "name": "John Brown", "avatar": "", "color": "#df532d", "type": "user" },
      { "id": 12, "name": "Anna Smith", "avatar": "", "color": "#1eb4aa", "type": "extranet" }
    ]
  }
}

Error response example

400 — userIds was not sent:

JSON 
{
  "success": false,
  "error": {
    "code": "INVALID_PARAMS",
    "message": "`userIds` is required: 1-50 Bitrix24 user ids separated by commas (4,7), each a positive integer without spaces or leading zeros."
  }
}

Errors

HTTP Code Description
400 INVALID_PARAMS userIds was not sent, more than 50 IDs were sent, or an ID is not a positive integer; or the request has a parameter other than userIds or a repeated parameter. Checked before any call to Bitrix24
403 SCOPE_DENIED The API key does not have the im scope
401 TOKEN_MISSING The API key has no Bitrix24 tokens configured
404 ENTITY_NOT_FOUND Bitrix24 answered "not found"; the portal code is in error.b24Code
422 BITRIX_ERROR Bitrix24 returned an error; the portal code is in error.b24Code. A chat that does not exist — CHAT_NOT_FOUND
502 ME_ALIAS_RESOLUTION_FAILED Failed to resolve the user when using the me alias
502 BITRIX_UNAVAILABLE Bitrix24 is unavailable or returned a server error

Full list of common API errors — Errors.

Known specifics

The call may make you a member. If the chat allows auto-join, Bitrix24 adds the caller as a member, as when opening a chat. This read-intent operation is allowed for a READONLY key under the narrow exception; it does not mark messages read. The im scope and the user's Bitrix24 access still apply.

See also