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.
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ohemorange and sydneyli Stop caching the results of ipv6_info in http01.py (#6411)
Stop caching the results of ipv6_info in http01.py. A call to choose_vhosts might change the ipv6 results of later calls. Add tests for this and default_listen_addresses more broadly.
Latest commit 22da244 Oct 17, 2018
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acme Bump version to 0.28.0 Sep 5, 2018
certbot-apache fix(apache): s/handle_mods/handle_modules (#6347) Sep 6, 2018
certbot-compatibility-test Remove CHANGES.rst (#6162) Sep 12, 2018
certbot-dns-cloudflare Bump version to 0.28.0 Sep 5, 2018
certbot-dns-cloudxns Bump version to 0.28.0 Sep 5, 2018
certbot-dns-digitalocean Bump version to 0.28.0 Sep 5, 2018
certbot-dns-dnsimple Bump version to 0.28.0 Sep 5, 2018
certbot-dns-dnsmadeeasy Bump version to 0.28.0 Sep 5, 2018
certbot-dns-gehirn Bump version to 0.28.0 Sep 5, 2018
certbot-dns-google Bump version to 0.28.0 Sep 5, 2018
certbot-dns-linode Bump version to 0.28.0 Sep 5, 2018
certbot-dns-luadns Bump version to 0.28.0 Sep 5, 2018
certbot-dns-nsone Bump version to 0.28.0 Sep 5, 2018
certbot-dns-ovh Correct OVH integration tests on machines without internet access (#6380 Sep 19, 2018
certbot-dns-rfc2136 Bump version to 0.28.0 Sep 5, 2018
certbot-dns-route53 Bump version to 0.28.0 Sep 5, 2018
certbot-dns-sakuracloud Bump version to 0.28.0 Sep 5, 2018
certbot-nginx Stop caching the results of ipv6_info in http01.py (#6411) Oct 17, 2018
certbot-postfix test(postfix): env for testing on oldest deps (#6230) Jul 18, 2018
certbot use safe args Sep 21, 2018
docs Fix typo in using.rst Oct 7, 2018
examples Update instances of acme-staging url to acme-staging-v02 (#5734) Mar 16, 2018
letsencrypt-auto-source Respect --quiet when reporting sudo invocation Sep 23, 2018
letshelp-certbot Advertise our packages work on Python 3.7. (#6183) Jul 9, 2018
tests update boulder integration test to check for new behavior Sep 21, 2018
tools Correct OVH integration tests on machines without internet access (#6380 Sep 19, 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 git ignore pytest cache (#6340) Sep 6, 2018
.pylintrc Add --disable=locally-enabled to .pylintrc. (#6159) Jun 28, 2018
.travis.yml Separate integration (#5814) Aug 29, 2018
AUTHORS.md make a list of contributors (#4508) Apr 26, 2017
CHANGELOG.md Stop caching the results of ipv6_info in http01.py (#6411) Oct 17, 2018
CONTRIBUTING.md Update CONTRIBUTING.md to be more welcoming. (#3540) Sep 26, 2016
Dockerfile Remove CHANGES.rst (#6162) Sep 12, 2018
Dockerfile-dev Cleanup dockerfile-dev (#5435) Feb 16, 2018
Dockerfile-old Remove CHANGES.rst (#6162) Sep 12, 2018
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 Remove CHANGES.rst (#6162) Sep 12, 2018
README.rst switch to codecov (#6220) Jul 31, 2018
appveyor.yml Connect AppVeyor to the certbot git repository (#6361) Sep 13, 2018
certbot-auto Candidate 0.27.1 (#6351) Sep 7, 2018
docker-compose.yml Cleanup dockerfile-dev (#5435) Feb 16, 2018
letsencrypt-auto Candidate 0.27.1 (#6351) Sep 7, 2018
linter_plugin.py Rename misc files Apr 14, 2016
local-oldest-requirements.txt Bump the acme version needed for account reuse (#6250) Jul 23, 2018
mypy.ini Get mypy passing with check_untyped_defs everywhere (#6021) May 22, 2018
pull_request_template.md Remind people to modify changelog when submitting PRs (#6341) Sep 6, 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 CHANGES.rst (#6162) Sep 12, 2018
tox.cover.sh switch to codecov (#6220) Jul 31, 2018
tox.ini bump pytest-xdist to 1.22.5 (#6253) Jul 31, 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.