> This page is for version v2 (default).
> For other versions, use one of these documentation indexes:
> - v2 (default): https://developers.clearpay.co.uk/v-2/llms.txt
> - v1: https://developers.clearpay.co.uk/v-1/llms.txt

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://developers.clearpay.co.uk/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://developers.clearpay.co.uk/_mcp/server.

# Request Headers

Clients must send appropriate headers with all requests.

## HTTP headers

| Field Name    | Requirement   | Description                                                                        |
| :------------ | :------------ | :--------------------------------------------------------------------------------- |
| Authorization | `required`    | See [Authentication](/authentication).                                             |
| Content-Type  | `required`    | All `POST` and `PUT` requests must declare the content-type as `application/json`. |
| User-Agent    | `required`    | See below.                                                                         |
| Accept        | `recommended` | All requests must accept `application/json` or `*/*`.                              |

## User-Agent header

User-Agent headers are used by the Clearpay team to identify API requests. You can use the following information to help generate your User-Agent header. User-Agent header must be supplied with all Merchant API requests prior to placing any live transactions.

For example: `MyClearpayModule/1.0.0 (E-Commerce Platform Name/1.0.0; PHP/7.0.0; Merchantname/60032000) https://merchant.example.com`

| Description          | Example Data Above               | Other Merchant Examples                                                                    |
| :------------------- | :------------------------------- | :----------------------------------------------------------------------------------------- |
| Clearpay Plugin      | `MyClearpayModule/1.0.0`         | • Custom Plugin/1.0 • Shopify Plugin/3.5.1 • ClearpayCartridge/1.0 • ClearpayExtension/2.9 |
| Platform             | `E-Commerce Platform Name/1.0.0` | • Websphere Commerce/8.1 • Commerce Cloud/1.1 • Adobe Commerce (Magento)/2.3.0             |
| System Information   | `PHP/7.0.0`                      | • PHP/7.2.18 • Ruby/2.5.3 • Java/8.3                                                       |
| Merchant ID          | `Merchantname/60032000`          | • Merchantname/101113200 • Merchantname/101931210                                          |
| Merchant Website URL | `https://merchant.example.com`   | • [http://www.merchantwebsite.com](http://www.merchantwebsite.com)                         |

> **Note:**
>
> In this case the Merchant ID is your company name or organisation name followed by an eight-digit number.