## Upload a file to a chat

`POST /v1/chats/:chatId/files`

Uploads a file to a chat. The content is passed in base64 and published in the chat as a message. Returns HTTP 201 with the identifier and metadata of the uploaded file.

## Parameters

| Parameter | Type | Required | Description |
|----------|-----|:-----:|---------|
| `chatId` (path) | number | yes | Chat ID. Get it: `POST /v1/chats` or `GET /v1/chats/recent` |

## Request fields (body)

| Field | Type | Required | Description |
|------|-----|:-----:|---------|
| `filename` | string | yes | File name with extension |
| `content` | string | yes | File content in base64 encoding |
| `message` | string | no | Message text attached to the file in the same message |

## Examples

### curl — personal key

```bash
curl -X POST https://vibecode.bitrix24.com/v1/chats/1001/files \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "filename": "report.pdf",
    "content": "aGVsbG8=",
    "message": "Report for the period"
  }'
```

### curl — OAuth application

```bash
curl -X POST https://vibecode.bitrix24.com/v1/chats/1001/files \
  -H "X-Api-Key: YOUR_APP_KEY" \
  -H "Authorization: Bearer USER_SESSION_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "filename": "report.pdf",
    "content": "aGVsbG8=",
    "message": "Report for the period"
  }'
```

### JavaScript — personal key

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/1001/files', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    filename: 'report.pdf',
    content: 'aGVsbG8=',
    message: 'Report for the period',
  }),
})

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

### JavaScript — OAuth application

```javascript
const res = await fetch('https://vibecode.bitrix24.com/v1/chats/1001/files', {
  method: 'POST',
  headers: {
    'X-Api-Key': 'YOUR_APP_KEY',
    'Authorization': 'Bearer USER_SESSION_TOKEN',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    filename: 'report.pdf',
    content: 'aGVsbG8=',
    message: 'Report for the period',
  }),
})

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

## Response fields

| Field | Type | Description |
|------|-----|---------|
| `success` | boolean | Always `true` on success |
| `data.fileId` | number | ID of the uploaded file. Use it for `GET /v1/chats/files/:fileId` |
| `data.name` | string | File name |
| `data.size` | string | File size in bytes |
| `data.downloadUrl` | string | File download link |

## Response example

```json
{
  "success": true,
  "data": {
    "fileId": 9265,
    "name": "report.pdf",
    "size": "24576",
    "downloadUrl": "https://YOUR_PORTAL.bitrix24.com/rest/download/?token=..."
  }
}
```

## Error response example

400 — required fields not provided:

```json
{
  "success": false,
  "error": {
    "code": "MISSING_PARAMS",
    "message": "Required: filename (string) and content (base64-encoded file content)"
  }
}
```

## Errors

| HTTP | Code | Description |
|------|-----|---------|
| 400 | `MISSING_PARAMS` | The required `filename` or `content` fields were not provided |
| 404 | `FOLDER_NOT_FOUND` | The chat folder on Drive was not found |
| 500 | `UPLOAD_FAILED` | The file upload did not complete |
| 422 | `BITRIX_ERROR` | Bitrix24 error during upload |
| 403 | `SCOPE_DENIED` | The key lacks the `im` scope |
| 401 | `TOKEN_MISSING` | The key has no configured Bitrix24 tokens |

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

## Known specifics

**Three steps in one call.** The upload is performed in three steps: getting the chat folder, uploading the file to Drive, publishing in the chat. If any step fails, the corresponding error is returned.

**The `message` parameter.** By passing `message`, you attach text to the same message as the file. A separate call to send the text is not needed.

**Base64 and body size.** Base64 encoding increases the request body size by about 33% compared to the original file.

## See also

- [Chat files](/docs/chats/files)
- [File metadata](/docs/chats/files/file-get)
- [Chat folder on Drive](/docs/chats/files/folder)
- [Send a message](/docs/chats/messages/send)