Introduction
************

Note: To get started quickly, use the interactive installation
  guide.

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.


Contributing
============

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


Installation
============

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.


Links
-----

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

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[image: Documentation status][image] [image: Docker Repository on
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System Requirements
-------------------

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