Foreign Data Wrappers for Cal.com allow developers to create event bookings directly from Postgres, simplifying signup forms and reducing transactions. Cal.com is an open-source scheduling platform that integrates well with various use cases and has a great developer toolkit. To set up the Foreign Data Wrappers, users need to sign up on Cal.com and Supabase, enable wrappers in their Supabase account, create a Wasm wrapper and foreign server, and set up foreign tables for Event Types and Bookings. Users can then query data from Cal.com using SQL queries, making it easy to extract scheduling information such as event types, bookings, and attendee details. The process also involves inserting booking records directly from Postgres, which are verified to appear on the upcoming list in Cal.com. The Foreign Data Wrappers for Cal.com are built with Wrappers, a framework for Postgres Foreign Data Wrappers, supporting Wasm for simplified development of API-based services.