Certbot vs Smallstep Certificate Manager

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.

Smallstep Certificate Manager has no write-up on Specifiction yet; its figures are above.