## Add comment

`POST /v1/timelines`

Creates a new timeline comment attached to a CRM record. Used to record notes on deals, leads, contacts and companies.

## Request fields (body)

| Field | Type | Req. | Description |
|------|-----|:-----:|---------|
| **`entityType`** | string | yes | Type of the parent CRM record: `deal`, `lead`, `contact`, `company` or `DYNAMIC_<entityTypeId>` for smart processes (e.g. `DYNAMIC_174` for a smart process with `entityTypeId: 174` from [`GET /v1/smart-processes`](/docs/entities/smart-processes/list)) |
| **`entityId`** | number | yes | Parent record ID. The source depends on the type: `GET /v1/deals`, `GET /v1/leads`, `GET /v1/contacts`, `GET /v1/companies`, `GET /v1/items/:entityTypeId` (smart-process items) |
| **`comment`** | string | yes | Comment text. An empty string is rejected with the error `BITRIX_ERROR Empty comment message` |
| `FILES` | array | no | Comment attachments. Each element is a two-string array `[fileName, base64Content]`. The field type in the Bitrix24 schema is `attached_diskfile` |

When created via the API, the author (`authorId`) is set from the API key owner, and the creation date (`createdAt`) by the server.

**Attaching files.** The `FILES` field is an array of `[fileName, base64Content]` pairs, one pair per file. The file content is passed as a base64-encoded string, the file is uploaded to Bitrix24 Drive and linked to the comment.

When reading the comment ([`GET /v1/timelines/:id`](/docs/entities/timelines/get)), attached files are returned in the `FILES` field — an object where the key is the Drive file ID and the value holds the metadata:

```json
"FILES": {
  "9317": {
    "id": 9317,
    "name": "report.pdf",
    "size": 11,
    "type": "file",
    "urlDownload": "https://vibecode.bitrix24.com/disk/downloadFile/9317/?filename=report.pdf"
  }
}
```

## Examples

### curl — personal key

```bash
curl -X POST https://vibecode.bitrix24.com/v1/timelines \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "entityType": "deal",
    "entityId": 741,
    "comment": "First contact: the client showed interest in the offer"
  }'
```

### curl — OAuth application

```bash
curl -X POST https://vibecode.bitrix24.com/v1/timelines \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "entityType": "deal",
    "entityId": 741,
    "comment": "First contact: the client showed interest in the offer"
  }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/timelines', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    entityType: 'deal',
    entityId: 741,
    comment: 'First contact: the client showed interest in the offer',
  }),
})

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

### JavaScript — OAuth application

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/timelines', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    entityType: 'deal',
    entityId: 741,
    comment: 'First contact: the client showed interest in the offer',
  }),
})

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

### curl — comment with a file

```bash
curl -X POST https://vibecode.bitrix24.com/v1/timelines \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "entityType": "deal",
    "entityId": 741,
    "comment": "Report attached",
    "FILES": [["report.pdf", "JVBERi0xLjQKJ..."]]
  }'
```

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `id` | number | ID of the created comment |
| `entityType` | string | Type of the parent record |
| `entityId` | number | Parent record ID |
| `comment` | string | Comment text |
| `authorId` | number | Author ID — when created via the API, matches the key owner |
| `createdAt` | datetime | Creation date (ISO 8601, UTC) |
| `FILES` | object | Attached files — only if any were passed. The key is the Drive file ID, the value holds the metadata: `name`, `size`, `type`, `urlDownload` |

## Response example

```json
{
  "success": true,
  "data": {
    "id": 66303,
    "entityId": 741,
    "entityType": "deal",
    "comment": "First contact: the client showed interest in the offer",
    "authorId": 1,
    "createdAt": "2026-04-24T12:34:05.000Z"
  }
}
```

## Error response example

422 — the required `comment` was not provided:

```json
{
  "success": false,
  "error": {
    "code": "BITRIX_ERROR",
    "message": "Empty comment message"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `INVALID_FILES_SHAPE` | The `FILES` field was not an array of `[[fileName, base64Content]]` pairs |
| 422 | `BITRIX_ERROR` | Requirement violation: empty `comment`, invalid `entityType` |
| 403 | `SCOPE_DENIED` | The API key lacks the `crm` scope |
| 401 | `TOKEN_MISSING` | The API key has no configured tokens |

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

## See also

- [List comments](/docs/entities/timelines/list) — verify created comments
- [Update comment](/docs/entities/timelines/update) — change the text
- [Delete comment](/docs/entities/timelines/delete)
- [Comment fields](/docs/entities/timelines/fields) — full field list
- [Batch](/docs/batch) — bulk comment creation
- [Limits and optimization](/docs/optimization) — rate limits