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Last pushed: a year ago
Short Description
Certbot, previously the Let's Encrypt Client.
Full Description

This file contains a series of comments that are used to include sections of this README in other files. Do not modify these comments unless you know what you are doing. tag:intro-begin

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 identify of web servers (e.g., is that really 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 issues 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

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

.. _installation:

The easiest way to install Certbot is by visiting, 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

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,, and, using the Apache plugin to both
obtain and install the certs, you could do this::

./certbot-auto --apache -d -d -d

(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 -d -d -d

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.

.. Do not modify this comment unless you know what you're doing. tag:links-begin


Software project:

Notes for developers:

Main Website:

Let's Encrypt Website:

IRC Channel: #letsencrypt on Freenode_


ACME spec:

ACME working area in github:

Mailing list: client-dev_ (to subscribe without a Google account, send an
email to

|build-status| |coverage| |docs| |container|

.. _Freenode:

.. _OFTC:

.. _client-dev:!forum/client-dev

.. |build-status| image::
:alt: Travis CI status

.. |coverage| image::
:alt: Coverage status

.. |docs| image::
:alt: Documentation status

.. |container| image::
:alt: Docker Repository on

.. Do not modify this comment unless you know what you're doing. tag:links-end

System Requirements
The Let's Encrypt Client presently only runs on Unix-ish OSes that include
Python 2.6 or 2.7; Python 3.x support will hopefully be added in the future. The
client requires root access in order to write to /etc/letsencrypt,
/var/log/letsencrypt, /var/lib/letsencrypt; to bind to ports 80 and 443
(if you use the standalone plugin) and to read and modify webserver
configurations (if you use the apache or nginx plugins). If none of
these apply to you, it is theoretically possible to run without root privileges,
but for most users who want to avoid running an ACME client as root, either
letsencrypt-nosudo or
simp_le are more appropriate choices.

The Apache plugin currently requires a Debian-based OS with augeas version
1.0; this includes Ubuntu 12.04+ and Debian 7+.

.. Do not modify this comment unless you know what you're doing. tag:intro-end

.. Do not modify this comment unless you know what you're doing. tag:features-begin

Current Features
Supports multiple web servers:

apache/2.x (beta support for auto-configuration)
nginx/0.8.48+ (alpha support for auto-configuration)
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 ncurses and text (-t) UI, or can be driven entirely from the
command line.
Free and Open Source Software, made with Python.
.. Do not modify this comment unless you know what you're doing. tag:features-end

For extensive documentation on using and contributing to Certbot, go to If you would like to contribute to the project or run the latest code from git, you should read our developer guide

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