Nginx

On a typical VPS, Nginx listens on ports 80 and 443, serves static files itself and forwards other requests to an app on a local port, such as Node.js on 3000 or Gunicorn for Python. It terminates HTTPS (often with free Let's Encrypt certificates from Certbot), compresses responses, caches, rate-limits and balances load across several app servers.

Its event-driven design handles many thousands of connections with little memory, which is why it runs a large share of the world's websites. Configuration lives in text files made of server and location blocks. F5 owns the company behind it and sells NGINX Plus with extra features and support; Caddy and Traefik are simpler alternatives with automatic HTTPS.