Backdrop is a full-featured content management system that allows non-technical users to manage a wide variety of content. It can be used to create all kinds of websites including blogs, image galleries, social networks, intranets, and more.

Backdrop aims to provide:

A CMS that can be used out-of-the-box.
Code that can be learned quickly.
Extensible APIs.

Requirements

PHP 5.3.2 or higher. Even if Backdrop can run on older versions of PHP, we strongly recommend that you use a supported version of PHP.
MySQL 5.0.15 or higher with PDO enabled
Apache (recommended) or Nginx web server
50 MB of disk space (recommended), 15 MB (minimum)

Installation

Create a new database, username, and password for Backdrop to use in MySQL.
Point your browser at the URL of your Backdrop installation. You will be redirected to the install screen. If you're not redirected, visit the install URL. If Backdrop was installed at http://example.com/backdrop, the install URL would be http://example.com/backdrop/core/install.php.
Follow the instructions provided by the installer.

Bug Reports and Feature Requests

Please use the GitHub issue tracker for reporting all bugs and features. We use a separate issue tracker that is not part of the main Backdrop code repository because of GitHub's restrictions on the use of labels and issue management.

Security Issues

If you have discovered a security issue with Backdrop CMS or any of its contributed modules, please contact the Backdrop Security Team directly at security@backdropcms.org. We manage security issues separately in a private repository until the issue has been resolved. Even if you're not sure if it's a security problem, please contact the security team before filing an issue.

Developers

Backdrop is a fork of Drupal. It preserves the legacy audience of developers who value ease of use and speed of learning over architectural flexibility. You can join Backdrop's developer community by forking Backdrop on GitHub.

When submitting a pull request, please make sure there is an open issue in the issue tracker and reference it in the description on the pull request.

Thanks to the following companies for providing sponsorship through services and products which may be used by Backdrop contributors to build and improve the project:

BrowserStack for interface testing across desktop and mobile browsers. (Contact info@backdropcms.org for access information.)
JetBrains for use of the PHPStorm IDE for development. (Contact info@backdropcms.org for a license.)
GitHub for collaboration and code management tools.
ZenCI for continuous automated testing and sandbox testing.

User Guide

Please see the the Backdrop Handbook.

Developer Documentation

Please see the the Backdrop API Documentation.

License

Backdrop is GPL v2 (or higher) software. See the LICENSE.txt file in the core directory for complete text. Distributions of this software may relicense it as any later version of the GPL.

Backdrop also includes works under different copyright notices that are distributed according to the terms of the GNU General Public License or a compatible license. These individual works may have specific copyright information noted within their source code files or directories.