On every request add the following headers:

X-RapidAPI-User
This should be your rapid api username. The API generates a unique Client Identifier based on this username so make sure that all YOUR requests use the same value.

X-RapidAPI-Key
This is the key provided by RapidAPI. Should be given to you when subscribing.

Thats it!. With these headers added, no authentication is needed. All your data is safely stored on AWS, and with the endpoints exposed you can easily Save (Single, Bulk), Delete (Single, Bulk) and Retrieve your transactions and portfolios!.