Certbot vs Let's Encrypt

Certbot is free, open-source software from the Electronic Frontier Foundation for enabling HTTPS on websites that administrators manage themselves. It obtains Let’s Encrypt certificates and can install them on a web server automatically in many cases. The command-line tool names Apache and Nginx integrations, along with webroot and standalone methods. DNS validation avoids requiring an inbound connection from Let’s Encrypt, so it does not depend on an existing HTTP site or an open port 80. Certbot renews certificates when less than one-third of their lifetime remains; for certificates lasting 10 days or less, renewal occurs when half their lifetime remains. It is generally run on a Unix-like server, often remotely over SSH, and is intended for administrators comfortable with command-line work on a dedicated server, VPS or cloud-hosted server. The project points users to its documentation and the Let’s Encrypt community forum for help.

Let’s Encrypt is a global Certificate Authority that provides SSL/TLS certificates for HTTPS connections. The ACME protocol verifies control of a domain, and compatible clients can automate issuance, management, and renewal. Its client directory includes Apache HTTP Server, Caddy, nginx, Kubernetes, Docker, and Windows/IIS environments. Certificates are Domain Validation only; Let’s Encrypt says it does not plan to issue Organization Validation or Extended Validation certificates. Wildcard certificates are available through the DNS-01 challenge. Standard certificates last 90 days, with an optional six-day lifetime; these periods cannot be adjusted. Subscribers generate and manage private keys on their own servers. Issued and revoked certificates are publicly recorded, and the service says its certificates are trusted by most browsers and operating systems. Certificates cost nothing. A registered domain can receive up to 50 certificates every seven days under published rate limits. Direct subscriber support is not offered.