HTTP functions allow you to expose the functionality of a Wix site as a service in the form of REST APIs. If you’ve added functionality to a site with code and want to use it in an app, you can expose HTTP functions and call the APIs in your app’s code. Learn more about Exposing a Site API with HTTP Functions.
The HTTP Functions API allows you to call your site’s HTTP functions with authentication context. Authentication context is information about who is calling an API. Calling HTTP functions directly doesn't provide them with authentication context, which restricts the Velo functions you can use in your code without overriding authentication using elevate().
Create an access token or an API Key to authorize the API call and to provide authentication context to your site’s HTTP functions.