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# RESTv1 to RESTv2 mapping

Understand the differences in headers and configuration between RESTv1 and RESTv2.

The following sections describe how headers and related configuration differ between RESTv1 and RESTv2.

## Security

The security configuration is the same in RESTv1 and RESTv2. Both versions use Basic authentication with:

* Username and password

* Account number and license key

## Profile header mapping

In RESTv1, client information is included in the request body.

In RESTv2, client information is sent using the `X-Avalara-Client` HTTP header.

> **Note**
>
> Part of the **RESTV1 To RESTV2 Refactor Guide**. [Open the full "RESTv1 to RESTv2 mapping" section on Avalara](https://developer.avalara.com/restv1-to-restv2-refactor-guide/eqm8525651286609/).