I am creating a saas project using vercel next js as FE and python supabase as BE. Tables created, RLA enabled. Python code written to access tables based on user. So far working everthing fine. User can access its own data only as implemented using supabase sdk. Now FE will be next js on vercel where i stuck. While user up or sign in, or ant any data operations, how will user name password or keys or tokens pass between FE and BE ie between next js and python securely? I have my functions api end points in python . Now i hv to connect python BE with frontend. Please suggest how to access / send data securely from frontend and maintain login n user session during multiple to n fro calls between FE and BE. And reference github or yourube for this?