Gateway Offloading: Centralizing Cross Cutting Concerns

What Is Offloading

Cross cutting concerns are features every service needs: authentication, logging, rate limiting, SSL termination. Without centralization, each service implements these independently, leading to inconsistent behavior and duplicated code. Gateway offloading moves these concerns to the gateway, implementing them once and applying them uniformly to all traffic.

Authentication and Authorization

The gateway validates tokens (JWT verification, OAuth token introspection) before requests reach services. Invalid requests are rejected at the edge, saving backend resources. The gateway can extract user identity and pass it to services via headers, so services trust the identity without re validating. Authorization decisions (can this user access this resource?) often remain in services where business context exists.

SSL Termination

HTTPS decryption at the gateway eliminates SSL overhead from every service. The gateway handles certificate management, renewal, and the CPU cost of encryption. Internal traffic between gateway and services can use plain HTTP over a trusted network, or mutual TLS (mTLS) where both parties verify certificates for zero trust architectures.

Observability Injection

The gateway generates consistent request IDs, adds tracing headers (correlation IDs that follow requests across services), and logs all requests in a standard format. Services receive these headers and propagate them, enabling distributed tracing. Centralized logging at the gateway captures the complete request lifecycle: arrival time, routing decision, backend latency, response code.

Request and Response Transformation

Add, remove, or modify headers before requests reach services. Inject tenant context, remove sensitive headers from responses, add caching headers. Transform request bodies for protocol translation or API versioning. Each transformation adds processing latency, so complex transformations may warrant dedicated translation services.