api-gateway

Membrane is a lightweight Java-based API gateway for authentication, request transformation, and routing. It sits between your clients and your backend services, inspecting and modifying requests as they flow through.

It can check authentication, throttle abusive clients, rewrite URLs, transform XML to JSON, and route traffic to different backends based on rules. The configuration is XML-based (this is a Java project, after all).

Membrane has been around since 2011 and is open source under Apache 2.0. It's a niche tool with a small but committed community. No paid tier, no cloud service.

The catch: this is old-school Java middleware. If you're in a modern cloud-native stack, Traefik or Kong are better choices with larger communities, better documentation, and Kubernetes integration. Membrane works but it feels like enterprise software from a different era. Unless you have a specific need for Membrane's SOAP/WSDL handling (it's strong there) or you're already in a Java shop, there are better options.