API gateways can simplify systems—or become chokepoints. The right pattern depends on ownership boundaries and the kind of change you expect.
01. Ownership boundaries
Gateways work best when teams can ship independently. A gateway that centralizes business logic increases coupling and slows delivery.
02. Cross-cutting concerns
Use gateways for auth, rate limits, routing, and observability. Keep domain logic behind service boundaries where it can be tested and evolved.
03. Contracts & versioning
Adopt explicit error models and versioning strategies. Contract tests reduce breakage and improve upgrade confidence.