## Add members

`POST /v1/chats/:chatId/users`

Adds one or more users to a group chat.

## Parameters

| Parameter | Type | Required | Description |
|----------|-----|:-----:|---------|
| `chatId` (path) | number | yes | Numeric chat ID (without the `chat` prefix) |

## Request fields (body)

| Field | Type | Required | Description |
|------|-----|:-----:|---------|
| `users` | number[] | yes | Array of user IDs to add |
| `hideHistory` | boolean | no | `true` — new members do not see the history before they joined, default `true`. `false` — the history is open from the moment the chat was created |

## Examples

### curl — personal key

```bash
curl -X POST "https://vibecode.bitrix24.com/v1/chats/123/users" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "users": [42, 53] }'
```

### curl — OAuth application

```bash
curl -X POST "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 '{ "users": [42, 53] }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/123/users', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ users: [42, 53] }),
})

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

### JavaScript — OAuth application

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/123/users', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ users: [42, 53] }),
})

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

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data` | boolean | `true` when added successfully |

## Response example

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

## Error response example

403 — the API key does not have the `im` scope:

```json
{
  "success": false,
  "error": {
    "code": "SCOPE_DENIED",
    "message": "This endpoint requires 'im' scope"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 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, chat not found or no permission) |
| 502 | `BITRIX_UNAVAILABLE` | Bitrix24 is unavailable or returned a server error |

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

## Known specifics

**Nonexistent users are skipped.** If the `users` array contains IDs of nonexistent or inactive users, they are ignored without an error. The operation is performed for the remaining members.

**History is hidden by default.** When adding without an explicit `hideHistory`, new members do not see messages sent before they joined. To give new members access to the history from when the chat was created, pass `hideHistory: false`.

## See also

- [Chat members](/docs/chats/members)
- [List members](/docs/chats/members/list)
- [Remove a member](/docs/chats/members/remove)
- [Chat management](/docs/chats/management)
- [Chats](/docs/chats)