Envoy

It's the data plane behind Istio, AWS App Mesh, and dozens of service meshes.

Everything is free under Apache 2.0. No paid tier from the Envoy project itself. It's a CNCF graduated project, which means it's been vetted for production use by the Cloud Native Computing Foundation. Maintained by a large contributor base including engineers from Google, Lyft (where it was created), and Microsoft.

Self-hosting is the only option, and the ops burden is significant. Envoy is powerful but complex. Configuration is verbose YAML. The learning curve is steep if you're not already in the service mesh world. Most teams don't run Envoy directly. They use it through Istio or a gateway controller. Solo developers: you don't need this. Use Nginx or Caddy. Small teams with a few services: still probably overkill. Use Traefik or Caddy. Growing teams with 10+ microservices: this is where Envoy starts making sense, especially through Istio or a gateway API.

The catch: Envoy is infrastructure for infrastructure people. The configuration complexity is legendary. Unless you're building a service mesh or need advanced traffic management (circuit breaking, retries, observability), simpler proxies do the job with 10% of the config.