> ## Documentation Index
> Fetch the complete documentation index at: https://alltick.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# WebSocket Common Standard Header

> This page defines the common standard headers and connection parameters for AllTick WebSocket market data interfaces, covering authentication-related fields, protocol version, compression, and more, so developers can establish secure and compatible connections for realtime quote streaming.

## Common Request Header Description

| Field   | Name            | Type   | Required                              | Description                                                                                                |
| ------- | --------------- | ------ | ------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| cmd\_id | Protocol number | uint32 | Provided in each interface definition |                                                                                                            |
| seq\_id | Sequence number | uint32 | Yes                                   | Generated uniquely by the requester. The response keeps the same value as the request.                     |
| trace   | Trace ID        | string | Yes                                   | Generated uniquely by the requester. The response keeps the same value as the request. Maximum length: 64. |
| data    | Data body       | object | Yes                                   | See each interface definition for the specific data format.                                                |

```json theme={null}
{
  "cmd_id": 22000,
  "seq_id": 123,
  "trace": "asdfsdfa",
  "data": {}
}
```

## Common Response Header Description

| Field   | Name            | Type   | Description                                                                                                |
| ------- | --------------- | ------ | ---------------------------------------------------------------------------------------------------------- |
| ret     | Return value    | int32  | [Error Code Description](/en/getting-started/error-code-description)                                       |
| msg     | Message         | string | Specific description of success or failure.                                                                |
| cmd\_id | Protocol number | uint32 | Provided in each interface definition.                                                                     |
| seq\_id | Sequence number | uint32 | Generated uniquely by the requester. The response keeps the same value as the request.                     |
| trace   | Trace ID        | string | Generated uniquely by the requester. The response keeps the same value as the request. Maximum length: 64. |
| data    | Data body       | object | See each interface definition for the specific data format.                                                |

```json theme={null}
{
  "ret": 201,
  "msg": "request header param invalid",
  "cmd_id": 0,
  "seq_id": 0,
  "trace": "",
  "data": {}
}
```

***

#### AllTick Website

<Note>
  Official website: <a href="https://alltick.co/">[https://alltick.co/](https://alltick.co/)</a>
</Note>

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