> This page is for Afterpay.

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

# Request headers

Merchants must send appropriate headers with all requests.

## HTTP headers

| Field Name    | Requirement | Description                                                                                   |
| ------------- | ----------- | --------------------------------------------------------------------------------------------- |
| Authorization | required    | See [Authentication](/cash-app-afterpay/api-reference/reference/introduction/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 Afterpay team to identify API requests. A User-Agent header must be supplied with all Merchant API requests prior to placing any live transactions.

For example: `MyAfterpayModule/1.0.0 (E-Commerce Platform Name/1.0.0; PHP/7.0.0; Merchantname/600032000) https://example.com`

| Description          | Example Data Above                         | Other Merchant Examples                                                            |
| -------------------- | ------------------------------------------ | ---------------------------------------------------------------------------------- |
| Afterpay Plugin      | MyAfterpayModule/1.0.0                     | Custom Plugin/1.0 Shopify Plugin/3.5.1 AfterpayCartridge/1.0 AfterpayExtension/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/600032000                     | Merchantname/101113200 Merchantname/101931210                                      |
| Merchant Website URL | [https://example.com](https://example.com) | [http://example.com](http://example.com)                                           |

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