The Proxy API leverages the authorization via Vault, so you can make requests directly to the integration without having to worry about the authentication for the connection.
This reference explains more details about our Proxy API:
An example of where we do a Proxy POST call directly to "quickbooks”:
where the x-apideck-downstream-url is the actual API endpoint of "Quickbooks".
The nice thing about the Proxy API is that the authentication is handled by Apideck Vault + you can see the request/response logs in Apideck.