API Gateway Patterns#

An API gateway sits between clients and your backend services. It handles cross-cutting concerns – authentication, rate limiting, request transformation, routing – so your services do not have to. Choosing the right gateway and configuring it correctly is one of the first decisions in any microservices architecture.

Gateway Responsibilities#

Before selecting a gateway, clarify which responsibilities it should own:

• Routing – directing requests to the correct backend service based on path, headers, or method.
• Authentication and authorization – validating tokens, API keys, or certificates before requests reach backends.
• Rate limiting – protecting backends from traffic spikes and enforcing usage quotas.
• Request/response transformation – modifying headers, rewriting paths, converting between formats.
• Load balancing – distributing traffic across service instances.
• Observability – emitting metrics, logs, and traces for every request that passes through.
• TLS termination – handling HTTPS so backends can speak plain HTTP internally.

No gateway does everything equally well. The right choice depends on which of these responsibilities matter most in your environment.