Envoy

Best for: teams running microservices that need a production-grade proxy and service mesh data plane.

Envoy is a cloud-native edge, middle and service proxy originally built at Lyft and now hosted by the Cloud Native Computing Foundation. Written in C++ for performance, it handles load balancing, observability, traffic routing and TLS termination, and serves as the data plane beneath service meshes including Istio.

What makes it useful: the observability is the differentiator. Envoy surfaces detailed statistics on every request passing through it, which turns opaque service-to-service traffic into something you can actually debug. Its universal data plane API means configuration can be driven dynamically rather than through static files and restarts.

Where it falls short: this is infrastructure for distributed systems, and the operational learning curve is steep — threading model, stats architecture and xDS configuration all take real study. For a solopreneur running a single application, Envoy is almost certainly more machinery than the problem requires. Its natural home is a team operating many services at meaningful scale.

Details: C++, Apache 2.0 licensed. CNCF graduated project.