KrakenD

KrakenD is an open source API gateway written in Go for building and securing microservice APIs. It is stateless, easy to operate, and built to scale out linearly with no single point of failure. The freely available Community Edition is the open source distribution.

It aggregates, composes, filters, and transforms responses from backend services, including XML-to-JSON conversion and back. On top of that it adds throttling, multi-layer rate limiting, concurrent calls, SSL and HTTP/2, and security controls such as CORS, OAuth, JWT, HSTS, and XSS protection. Configuration is declarative and GitOps-friendly.

KrakenD is platform-agnostic, running cloud-native or self-hosted on-premises, and ships in several formats including an official Docker image. Behavior can be extended with Go plugins, Lua scripts, Martian, and Google CEL.