.. notice for github users
The Let's Encrypt Client is BETA SOFTWARE. It contains plenty of bugs and
rough edges, and should be tested thoroughly in staging environments before use
on production systems.
For more information regarding the status of the project, please see
https://letsencrypt.org. Be sure to checkout the
Frequently Asked Questions (FAQ) <https://community.letsencrypt.org/t/frequently-asked-questions-faq/26#topic-title>_.
About the Let's Encrypt Client
The Let's Encrypt Client is a fully-featured, extensible client for the Let's
Encrypt CA (or any other CA that speaks the
protocol) that can automate the tasks of obtaining certificates and
configuring webservers to use them. This client runs on Unix-based operating
letsencrypt is packaged for your Unix OS, you can install it from
there, and run it by typing
letsencrypt. Because not all operating
systems have packages yet, we provide a temporary solution via the
letsencrypt-auto wrapper script, which obtains some dependencies
from your OS and puts others in a python virtual environment::
user@webserver:~$ git clone https://github.com/letsencrypt/letsencrypt
user@webserver:~$ cd letsencrypt
user@webserver:~/letsencrypt$ ./letsencrypt-auto --help
Or for full command line help, type::
./letsencrypt-auto --help all
letsencrypt-auto updates to the latest client release automatically. And
letsencrypt-auto is a wrapper to
letsencrypt, it accepts exactly
the same command line flags and arguments. More details about this script and
other installation methods can be found
in the User Guide
How to run the client
In many cases, you can just run
letsencrypt, and the
client will guide you through the process of obtaining and installing certs
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
other.example.net, using the Apache plugin to both
obtain and install the certs, you could do this::
./letsencrypt-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
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::
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
plugins <https://letsencrypt.readthedocs.org/en/latest/using.html#plugins>_ in
the User Guide.
Software project: https://github.com/letsencrypt/letsencrypt
Notes for developers: https://letsencrypt.readthedocs.org/en/latest/contributing.html
Main Website: https://letsencrypt.org/
IRC Channel: #letsencrypt on
ACME spec: http://ietf-wg-acme.github.io/acme/
ACME working area in github: https://github.com/ietf-wg-acme/acme
client-dev_ (to subscribe without a Google account, send an
email to firstname.lastname@example.org)
|build-status| |coverage| |docs| |container|
.. |build-status| image:: https://travis-ci.org/letsencrypt/letsencrypt.svg?branch=master
:alt: Travis CI status
.. |coverage| image:: https://coveralls.io/repos/letsencrypt/letsencrypt/badge.svg?branch=master
:alt: Coverage status
.. |docs| image:: https://readthedocs.org/projects/letsencrypt/badge/
:alt: Documentation status
.. |container| image:: https://quay.io/repository/letsencrypt/letsencrypt/status
:alt: Docker Repository on Quay.io
.. _watch demo video: https://www.youtube.com/watch?v=Gas_sSB-5SU
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 be added after the Public Beta
launch. The client requires root access in order to write to
bind to ports 80 and 443 (if you use the
standalone plugin) and to read and
modify webserver configurations (if you use the
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
<https://github.com/kuba/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+.
Supports multiple web servers:
- apache/2.x (working on Debian 8+ and Ubuntu 12.04+)
- standalone (runs its own simple webserver to prove you control a domain)
- webroot (adds files to webroot directories in order to prove control of
domains and obtain certs)
- nginx/0.8.48+ (highly experimental, not included in letsencrypt-auto)
The private key is generated locally on your system.
- Can talk to the Let's Encrypt CA or optionally to other ACME
- 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
- Free and Open Source Software, made with Python.
.. _Freenode: https://webchat.freenode.net?channels=%23letsencrypt
.. _client-dev: https://groups.google.com/a/letsencrypt.org/forum/#!forum/client-dev