## Remove a member

`DELETE /v1/chats/:chatId/users`

Removes one user from a group chat.

## Parameters

| Parameter | Type | Required | Description |
|----------|-----|:-----:|---------|
| `chatId` (path) | number | yes | Numeric chat ID (without the `chat` prefix) |
| `format` (query) | string | no | `v2` turns on the v2 mode — see "The v2 mode" below. Any other value is ignored and the response is unchanged. A repeated `format` is not rejected: with `format=v1&format=v2` the last value wins, so the v2 mode is on, while `format=v2&format=v1` returns the legacy response. The bracket form `format[]=v2` turns on the v2 mode when all its values are `v2` |

## Request fields (body)

| Field | Type | Required | Description |
|------|-----|:-----:|---------|
| `userId` | number | yes | ID of the user to remove — a positive integer: a number, or a string of decimal digits without leading zeros or spaces, up to 2^53−1; any other shape is refused before Bitrix24 is called |

**The v2 mode.** `format=v2` removes the member through the v2 messenger with the same body `{ "userId": … }`. The Bitrix24 spelling `USER_ID`, other body fields and query parameters are rejected with `400 INVALID_PARAMS`. `data` carries `{ "result": true }` instead of `true`. Removing a user who is not in the chat returns `422 BITRIX_ERROR` with `error.b24Code` `USER_NOT_FOUND`.

## Examples

### curl — personal key

```bash
curl -X DELETE "https://vibecode.bitrix24.com/v1/chats/123/users" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "userId": 42 }'
```

### curl — OAuth application

```bash
curl -X DELETE "https://vibecode.bitrix24.com/v1/chats/123/users" \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "userId": 42 }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/123/users', {
  method: 'DELETE',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ userId: 42 }),
})

const { success, data } = await res.json()
console.log('Removed:', data)
```

### JavaScript — OAuth application

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/123/users', {
  method: 'DELETE',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ userId: 42 }),
})

const { success, data } = await res.json()
```

### curl — the v2 mode

```bash
curl -X DELETE "https://vibecode.bitrix24.com/v1/chats/123/users?format=v2" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "userId": 42 }'
```

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data` | boolean | `true` when removed successfully |
| `data.result` | boolean | The v2 mode: `true` — the member was removed |

## Response example

```json
{
  "success": true,
  "data": true
}
```

## Error response example

422 — the user is not a member of the chat:

```json
{
  "success": false,
  "error": {
    "code": "BITRIX_ERROR",
    "message": "The specified user is not a member of the chat"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `INVALID_CHAT_ID` | `chatId` is not a positive integer — checked before the Bitrix24 call |
| 400 | `MISSING_PARAMS` | The `userId` field is absent (including a request with no body at all) |
| 400 | `INVALID_PARAMS` | `userId` is not a positive integer in canonical form — an array, a word, zero, a negative or fractional value, a value with leading zeros or spaces, or a value above 2^53−1. In the v2 mode also a query parameter other than `format`, a body field other than `userId`, or a body that is not a JSON object. Nothing was sent to Bitrix24 |
| 403 | `WRITE_BLOCKED_READONLY_KEY` | The key is read-only — see [access rights](/docs/access-rights) |
| 403 | `SCOPE_DENIED` | The API key does not have the `im` scope |
| 401 | `TOKEN_MISSING` | The API key has no configured Bitrix24 tokens |
| 422 | `BITRIX_ERROR` | Bitrix24 returned an error — the text is in the `message` field (for example, the user is not a member of the chat, or there is no permission). The Bitrix24 code is in `error.b24Code`. Without `format`, removing a member from a collab chat returns this error with `ACCESS_ERROR` and the text `It is forbidden to delete users of this chat`. In the v2 mode the member is removed |
| 502 | `BITRIX_UNAVAILABLE` | Bitrix24 is unavailable or returned a server error |

Full list of common API errors — [Errors](/docs/errors).

## Known specifics

**One member at a time.** The endpoint accepts a single `userId` (a number), not an array. To remove several members, call the method for each one separately.

**Numeric ID only.** Bitrix24 casts `userId` to a number by PHP rules: the array `[47]` becomes `1` — the user with ID 1, usually the Bitrix24 account owner, would be removed from the chat instead of user 47. So the API checks the shape of the value itself: it accepts a number or a string of decimal digits without leading zeros or spaces, and returns `400 INVALID_PARAMS` for anything else.

**Only `chatId` and `userId` are sent to Bitrix24.** Other fields of the request body are not forwarded to Bitrix24 — including native upper-case Bitrix24 keys. Bitrix24 treats parameter names as case-insensitive, and the last key wins: the body `{"USER_ID": 47, "user_id": [1]}` would pass the check on `USER_ID`, yet the alias would win in Bitrix24 — the user with ID 1 would be removed from the chat.

## See also

- [Chat members](/docs/chats/members)
- [List members](/docs/chats/members/list)
- [Add members](/docs/chats/members/add)
- [Permission management](/docs/chats/management/owner)
- [Chats](/docs/chats)