Backend for Frontend (BFF) -- API gateway per client type

Mobile, web, and third-party API consumers have different data needs. A single generic API either over-fetches (sends too much data to mobile) or requires multiple round-trips (web needs data from several microservices).

Create a dedicated BFF service for each client type (web BFF, mobile BFF, admin BFF). Each BFF: aggregates data from multiple microservices, formats responses for its specific client, handles client-specific auth flows, manages client-specific caching. This keeps backend services generic while giving each frontend exactly what it needs.

Different clients have different constraints: mobile has limited bandwidth, web needs different data shapes, admin needs full access. A single API cannot optimize for all clients simultaneously.