## Check access to a chat or message

`GET /v1/chats/access`

Checks whether the current user can open a chat, a message or both — the v2 messenger method `im.v2.Access.check`. If the user has access, the response is `data.result: true`. If not, the response is an error rather than `false`: `403 BITRIX_ACCESS_DENIED`, or `422 BITRIX_ERROR` when the chat or the message does not exist in the Bitrix24 account.

## Parameters

| Parameter | Type | Required | Description |
|----------|-----|:-----:|---------|
| `dialogId` (query) | string | no | The chat to check: `chatN` for a group chat, a numeric user ID for a personal dialog, `me` — the current user's personal dialog |
| `messageId` (query) | number | no | The message to check — a positive integer |

At least one of the two parameters is required: if neither is passed, there is nothing to check and the request is rejected with `400 MISSING_PARAMS`. Other or repeated parameters are rejected with `400 INVALID_PARAMS` before any call to Bitrix24.

## Examples

### curl — personal key

```bash
curl "https://vibecode.bitrix24.com/v1/chats/access?dialogId=chat42" \
  -H "X-Api-Key: YOUR_API_KEY"
```

### curl — OAuth application

```bash
curl "https://vibecode.bitrix24.com/v1/chats/access?dialogId=chat42" \
  -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/access?messageId=1002', {
  headers: { 'X-Api-Key': 'YOUR_API_KEY' },
})

// No access is an error, not result: false
const canOpen = res.ok && (await res.json()).data.result === true
console.log('Message accessible:', canOpen)
```

### JavaScript — OAuth application

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/access?messageId=1002', {
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
  },
})

const canOpen = res.ok && (await res.json()).data.result === true
```

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data.result` | boolean | Always `true`: access granted |

## Response example

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

## Error response example

422 — the message does not exist in the Bitrix24 account:

```json
{
  "success": false,
  "error": {
    "code": "BITRIX_ERROR",
    "message": "MESSAGE_NOT_FOUND",
    "b24Code": "MESSAGE_NOT_FOUND"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `MISSING_PARAMS` | Neither `dialogId` nor `messageId` was passed |
| 400 | `INVALID_PARAMS` | `messageId` is not a positive integer, `dialogId` is empty, or the request has a parameter other than `dialogId` and `messageId` or a repeated parameter |
| 403 | `BITRIX_ACCESS_DENIED` | No access to the chat or the message |
| 404 | `ENTITY_NOT_FOUND` | Bitrix24 returned "not found"; the portal code is in `error.b24Code` |
| 422 | `BITRIX_ERROR` | Bitrix24 returned an error; the portal code is in `error.b24Code`. `CHAT_NOT_FOUND` — the chat does not exist on the portal, `MESSAGE_NOT_FOUND` — the message does not exist |
| 502 | `ME_ALIAS_RESOLUTION_FAILED` | Failed to resolve the user when using the `me` alias |
| 403 | `SCOPE_DENIED` | The API key does not have the `im` scope |
| 401 | `TOKEN_MISSING` | The API key has no Bitrix24 tokens configured |

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

## Known specifics

**The checks are independent.** With both parameters Bitrix24 checks the chat and the message separately and does not verify that the message belongs to that chat. To find the chat of a message, open the chat [around the message](/docs/chats/messages/load-in-context).

**The check may make you a member.** The check follows the same path as opening the chat: when the chat allows auto-join — a comment chat, a collab or a task chat, for example — the call adds the current user as a member. This exact read operation is allowed for a `READONLY` key, subject to the `im` scope and the user's Bitrix24 access. It does not mark messages read.

## See also

- [Chat discovery](/docs/chats/discovery)
- [Dialog details](/docs/chats/discovery/get)
- [Load a chat](/docs/chats/messages/load)