## Bind

`POST /v1/activities/:activityId/bindings`

Binds an activity to an additional CRM entity — it appears in that entity's timeline alongside the owner entity.

## Parameters

| Parameter | Type | Required | Description |
|----------|-----|:-----:|---------|
| `activityId` (path) | number | yes | Activity ID. List: `GET /v1/activities` |

## Request fields (body)

| Field | Type | Required | Description |
|------|-----|:-----:|---------|
| **`entityTypeId`** | number | yes | Numeric CRM entity-type code:<br>1 — lead<br>2 — deal<br>3 — contact<br>4 — company<br>7 — quote<br>31 — invoice<br>≥128 — smart-process, its code — in [`GET /v1/smart-processes`](/docs/entities/smart-processes/list) |
| **`entityId`** | number | yes | ID of the entity to bind to |

## Examples

### curl — personal key

```bash
curl -X POST https://vibecode.bitrix24.com/v1/activities/3631/bindings \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "entityTypeId": 3, "entityId": 9 }'
```

### curl — OAuth app

```bash
curl -X POST https://vibecode.bitrix24.com/v1/activities/3631/bindings \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "entityTypeId": 3, "entityId": 9 }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/activities/3631/bindings', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ entityTypeId: 3, entityId: 9 }),
})

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

### JavaScript — OAuth app

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/activities/3631/bindings', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ entityTypeId: 3, entityId: 9 }),
})

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

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data.activityId` | number | Activity ID |
| `data.entityTypeId` | number | Numeric type code of the bound entity |
| `data.entityId` | number | ID of the bound entity |
| `data.bound` | boolean | Always `true` — confirmation of the binding |

## Response example

```json
{
  "success": true,
  "data": {
    "activityId": 3631,
    "entityTypeId": 3,
    "entityId": 9,
    "bound": true
  }
}
```

## Error response example

422 — the entity is already bound:

```json
{
  "success": false,
  "error": {
    "code": "BITRIX_ERROR",
    "message": "Activity is already bound to this entity"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `INVALID_PARAMS` | `activityId`, `entityTypeId` or `entityId` is not a positive integer |
| 404 | `ENTITY_NOT_FOUND` | No activity exists for the given `activityId` |
| 422 | `BITRIX_ERROR` | The activity is already bound to this `entityTypeId` + `entityId` pair, or no such entity exists |
| 403 | `SCOPE_DENIED` | The key lacks the `crm` scope |
| 401 | `TOKEN_MISSING` | The key has no configured tokens |

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

## Known specifics

**Binding is not idempotent.** A repeated request for an already-bound pair returns `422`, not `200`. It means "already bound", not a failure — there is no need to retry, and no duplicate is added to the list.

## See also

- [Unbind](/docs/entities/activities/bindings/unbind)
- [List bindings](/docs/entities/activities/bindings/list)
- [Activities](/docs/entities/activities)