ACME

Definition

Automatic Certificate Management Environment (ACME) is an IETF protocol for proving domain control and obtaining TLS certificates without a human signing CSRs. Let's Encrypt is the dominant ACME CA; certbot, Caddy, Traefik, and nginx-proxy-manager are common clients. Most modern reverse proxies handle ACME renewal automatically, eliminating expired-cert outages.

When to use

See also

• TLS — The protocol that encrypts HTTP and other connections — what the lock icon in browsers actually means.
• Caddy — Modern reverse proxy and web server with automatic HTTPS via Let's Encrypt — a simpler alternative to nginx.