Certbot is EFF's tool to obtain certs from Let's Encrypt and (optionally) auto-enable HTTPS on your server. It can also act as a client for any other CA that uses the ACME protocol.
Python Shell Batchfile Makefile Augeas C
Switch branches/tags
Clone or download
schoen Merge pull request #6211 from greut/num-processes
travis: container env are bad at reading cpu count
Latest commit 0f833c6 Jul 16, 2018
Failed to load latest commit information.
acme Bump version to 0.27.0 Jul 11, 2018
certbot-apache Bump version to 0.27.0 Jul 11, 2018
certbot-compatibility-test Bump version to 0.27.0 Jul 11, 2018
certbot-dns-cloudflare Bump version to 0.27.0 Jul 11, 2018
certbot-dns-cloudxns Bump version to 0.27.0 Jul 11, 2018
certbot-dns-digitalocean Bump version to 0.27.0 Jul 11, 2018
certbot-dns-dnsimple Bump version to 0.27.0 Jul 11, 2018
certbot-dns-dnsmadeeasy Bump version to 0.27.0 Jul 11, 2018
certbot-dns-gehirn Bump version to 0.27.0 Jul 11, 2018
certbot-dns-google Bump version to 0.27.0 Jul 11, 2018
certbot-dns-linode Fixed linode API settings page URL (#6208) Jul 16, 2018
certbot-dns-luadns Bump version to 0.27.0 Jul 11, 2018
certbot-dns-nsone Bump version to 0.27.0 Jul 11, 2018
certbot-dns-ovh Bump version to 0.27.0 Jul 11, 2018
certbot-dns-rfc2136 Bump version to 0.27.0 Jul 11, 2018
certbot-dns-route53 Bump version to 0.27.0 Jul 11, 2018
certbot-dns-sakuracloud Bump version to 0.27.0 Jul 11, 2018
certbot-nginx Bump version to 0.27.0 Jul 11, 2018
certbot-postfix Advertise our packages work on Python 3.7. (#6183) Jul 9, 2018
certbot fix account tests (#6216) Jul 16, 2018
docs Merge pull request #6206 from certbot/candidate-0.26.0 Jul 16, 2018
examples Update instances of acme-staging url to acme-staging-v02 (#5734) Mar 16, 2018
letsencrypt-auto-source Bump version to 0.27.0 Jul 11, 2018
letshelp-certbot Advertise our packages work on Python 3.7. (#6183) Jul 9, 2018
tests Separate integration coverage (#6113) Jun 15, 2018
tools update venv3.sh to include dns-rfc2136 plugin (#6226) Jul 16, 2018
.coveragerc Switch from nose to pytest (#5282) Dec 1, 2017
.dockerignore Update ignore files to remove shared tox.venv Jul 12, 2015
.gitattributes Merge pull request #2136 from tboegi/gitattributes_eol_overrideses_auto Jun 16, 2016
.gitignore Get mypy tox env running in the current setup (#5861) Apr 12, 2018
.pylintrc Add --disable=locally-enabled to .pylintrc. (#6159) Jun 28, 2018
.travis.yml travis: container env are bad at reading cpu count Jul 12, 2018
AUTHORS.md make a list of contributors (#4508) Apr 26, 2017
CHANGELOG.md Add 0.26.0 changelog (#6205) Jul 16, 2018
CHANGES.rst Improve CHANGES.rst. (#3541) Sep 27, 2016
CONTRIBUTING.md Update CONTRIBUTING.md to be more welcoming. (#3540) Sep 26, 2016
Dockerfile Updated base image to python:2-alpine3.7 (#5889) Apr 20, 2018
Dockerfile-dev Cleanup dockerfile-dev (#5435) Feb 16, 2018
Dockerfile-old add certbot wrapper to Dockerfile-old Mar 7, 2017
ISSUE_TEMPLATE.md Suggest people try the community forum. (#5561) Feb 10, 2018
LICENSE.txt More stray ncrypt reference cleanup Apr 15, 2016
MANIFEST.in Use ffdhe2048 Nginx DH params to fix Weak-DH bug (#4973) Sep 1, 2017
README.rst Link to changelog from readme (#5069) Sep 1, 2017
certbot-auto Release 0.26.0 Jul 11, 2018
docker-compose.yml Cleanup dockerfile-dev (#5435) Feb 16, 2018
letsencrypt-auto Release 0.26.0 Jul 11, 2018
linter_plugin.py Rename misc files Apr 14, 2016
local-oldest-requirements.txt Used packaged acme in oldest tests. (#6112) Jun 15, 2018
mypy.ini Get mypy passing with check_untyped_defs everywhere (#6021) May 22, 2018
readthedocs.org.requirements.txt RTD: install local deps for subpkgs (fixes #1086). Oct 23, 2015
setup.cfg Switch from nose to pytest (#5282) Dec 1, 2017
setup.py Remove main components from Alpha. (#6187) Jul 10, 2018
tox.cover.sh travis: container env are bad at reading cpu count Jul 12, 2018
tox.ini travis: container env are bad at reading cpu count Jul 12, 2018


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 interactive guide. It generates instructions based on your configuration settings. In most cases, you’ll need root or administrator access to your web server to run Certbot.

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 ACME protocol) that can automate the tasks of obtaining certificates and configuring webservers to use them. This client runs on Unix-based operating systems.

To see the changes made to Certbot between versions please refer to our 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.


If you'd like to contribute to this project please read Developer Guide.


The easiest way to install Certbot is by visiting certbot.eff.org, where you can find the correct installation instructions for many web server and OS combinations. For more information, see Get Certbot.

How to run the client

In many cases, you can just run certbot-auto or certbot, and the client will guide you through the process of obtaining and installing certs interactively.

For full command line help, you can type:

./certbot-auto --help all

You can also tell it exactly what you want it to do from the command line. For instance, if you want to obtain a cert for example.com, www.example.com, and other.example.net, using the Apache plugin to both obtain and install the certs, you could do this:

./certbot-auto --apache -d example.com -d www.example.com -d other.example.net

(The first time you run the command, it will make an account, and ask for an email and agreement to the Let's Encrypt Subscriber Agreement; you can automate those with --email and --agree-tos)

If you want to use a webserver that doesn't have full plugin support yet, you can still use "standalone" or "webroot" plugins to obtain a certificate:

./certbot-auto certonly --standalone --email admin@example.com -d example.com -d www.example.com -d other.example.net

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 explanation of plugins in the User Guide.


Documentation: https://certbot.eff.org/docs

Software project: https://github.com/certbot/certbot

Notes for developers: https://certbot.eff.org/docs/contributing.html

Main Website: https://certbot.eff.org

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

IRC Channel: #letsencrypt on Freenode

Community: https://community.letsencrypt.org

ACME spec: http://ietf-wg-acme.github.io/acme/

ACME working area in github: https://github.com/ietf-wg-acme/acme

Travis CI status Coverage status Documentation status Docker Repository on Quay.io

System Requirements

See https://certbot.eff.org/docs/install.html#system-requirements.

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 third party plugins
  • The private key is generated locally on your system.
  • Can talk to the Let's Encrypt CA or optionally to other ACME compliant services.
  • Can get domain-validated (DV) certificates.
  • Can revoke certificates.
  • Adjustable RSA key bit-length (2048 (default), 4096, ...).
  • Can optionally install a http -> https redirect, so your site effectively runs https only (Apache only)
  • Fully automated.
  • Configuration changes are logged and can be reverted.
  • Supports an interactive text UI, or can be driven entirely from the command line.
  • Free and Open Source Software, made with Python.

For extensive documentation on using and contributing to Certbot, go to 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 developer guide.