Let's Encrypt
A free, automated certificate authority that issues the TLS certificates used to enable HTTPS.
Reverse proxies like Caddy, Traefik and Nginx Proxy Manager obtain and renew Let's Encrypt certificates automatically, so your services get valid HTTPS with no manual work.
Related articles
TLS/SSL
The encryption that secures connections, shown as the padlock and https:// in your browser.
Reverse Proxy
A server that sits in front of your services, routing requests by domain name and handling TLS certificates.