Backend for Frontend (BFF)

A mobile app needs a compact account summary; a web dashboard needs detailed tables. Both gather data from several services. Making each frontend assemble these responses adds network requests and client logic, while a shared API must accommodate different screen requirements.

A Backend for Frontend (BFF) is a backend dedicated to a particular frontend. It calls the underlying services and combines and shapes their data for that frontend's screens.

Mobile app → Mobile BFF → Shared services
Web dashboard → Web BFF → Shared services

Each frontend team can evolve its responses independently, at the cost of another service to run and an extra network hop.