Certbot is part of EFF’s effort to encrypt the entire Internet. Secure communication over the Web relies on HTTPS, which requires the use of a digital certificate that lets browsers verify the identity of web servers (e.g., is that really google.com?). Web servers obtain their certificates from trusted third parties called certificate authorities (CAs). Certbot is an easy-to-use client that fetches a certificate from Let’s Encrypt—an open certificate authority launched by the EFF, Mozilla, and others—and deploys it to a web server.

Anyone who has gone through the trouble of setting up a secure website knows what a hassle getting and maintaining a certificate is. Certbot and Let’s Encrypt can automate away the pain and let you turn on and manage HTTPS with simple commands. Using Certbot and Let's Encrypt is free, so there’s no need to arrange payment.

How you use Certbot depends on the configuration of your web server. The best way to get started is to use our root or administrator access to your web server to run Certbot.

Certbot is meant to be run directly on your web server, not on your personal computer. If you’re using a hosted service and don’t have direct access to your web server, you might not be able to use Certbot. Check with your hosting provider for documentation about uploading certificates or using certificates issued by Let’s Encrypt.

Certbot is a fully-featured, extensible client for the Let's Encrypt CA (or any other CA that speaks the changelog.

Until May 2016, Certbot was named simply letsencrypt or letsencrypt-auto, depending on install method. Instructions on the Internet, and some pieces of the software, may still refer to this older name.

Contributing

If you'd like to contribute to this project please read EFF's Public Projects Code of Conduct.

How to run the client

The easiest way to install and run Certbot is by visiting Get Certbot.

Understanding the client in more depth

To understand what the client is doing in detail, it's important to understand the way it uses plugins. Please see the Links

Documentation: https://github.com/certbot/certbot

Notes for developers: https://certbot.eff.org

Let's Encrypt Website: https://community.letsencrypt.org

ACME spec: https://github.com/ietf-wg-acme/acme

System Requirements

See Current Features

• Supports multiple web servers:
  • apache/2.x
  • nginx/0.8.48+
  • webroot (adds files to webroot directories in order to prove control of domains and obtain certs)
  • standalone (runs its own simple webserver to prove you control a domain)
  • other server software via https://certbot.eff.org/docs. If you would like to contribute to the project or run the latest code from git, you should read our /icbugcoder/letsencrypt