Backend & systems·API and interface design
you build a separate thin API for the mobile app so it stops being shaped by whatever the web client needed.
Backend for frontend
Also calledBFF
A per-client aggregation layer that shapes and combines downstream services for one consumer. It lets each client evolve without negotiating with the others and removes chatty round trips on slow networks. The cost is another deployable per client, and duplicated logic if the boundary drifts.