axum-impl-tower-stack

Axum middleware ordering depends on whether you use ServiceBuilder or stacked Router::layer() calls, as ServiceBuilder applies layers in reverse declaration order while Router::layer() applies them outermost-first. Matching the two prevents unexpected request processing behavior.

tower-http layers often fail to compile because specific Cargo feature flags must be explicitly enabled for components like CorsLayer, CompressionLayer, and TraceLayer. Enabling the correct tower-http features resolves the missing trait implementation errors.

tower::limit provides coarse global throughput throttling, whereas tower_governor implements per-client token bucket rate limiting. tower_governor requires its service to be Clone or wrapped in a BufferLayer to satisfy backpressure contracts.

Production-safe CORS in Axum requires configuring CorsLayer with explicit origin allowlists rather than using permissive presets. Defining specific allowed origins prevents unauthorized cross-origin requests from reaching your application.

Yes, RateLimitLayer requires non-Clone services to be wrapped in a BufferLayer to properly handle the poll_ready backpressure contract. Wrapping the service ensures correct rate limiting behavior without panicking under load.

Common limitations include violating the poll_ready backpressure contract, misordering ServiceBuilder versus Router::layer() outermost layers, and missing required tower-http Cargo features. Adhering to layer ordering and feature enablement rules avoids these middleware stack failures.