Krakend

KrakenD Community Edition is the open source distribution of the KrakenD API gateway. It sits between clients and existing services so new APIs can be published without changing the contracts the backends already expose.

Statelessness is the decision everything else follows from. Every node runs on its own with no coordination and no centralized persistence, so there is no single point of failure and scaling out means adding instances. Configuration is declarative and versioned like any other file, putting the API lifecycle under GitOps. The project reports over 70,000 requests per second on one regular sized instance, with memory usually under 50MB at more than 1000 concurrent connections.

The feature set covers the work a gateway normally absorbs.

• Aggregation: compose, filter and merge content from several APIs into a single view.
• Transformation: rewrite responses and convert between XML and JSON in either direction.
• Security: zero trust policy, CORS, OAuth, JWT, HSTS, clickjacking protection and XSS protection.
• Rate limiting: throttle in the router and proxy layers, with bursting, load balancing and a circuit breaker.
• Telemetry: report to Datadog, Zipkin, Jaeger, Prometheus and Grafana.
• Extensibility: add behavior with Go plugins, Lua scripts, Martian or Google CEL expressions.

Distribution is by package or official Docker image, so a running gateway is one container and one configuration file away, and cloning the repository is only needed to build the binary yourself. It runs the same on Kubernetes or on hardware in your own rack, and deliberately leaves telemetry backends and identity providers to the tools you already have.