The source of GitLab Community Edition is [hosted on GitLab.com](https://gitlab.com/gitlab-org/gitlab-ce/) and there are mirrors to make [contributing](CONTRIBUTING.md) as easy as possible.
- GitLab Community Edition (CE) is available freely under the MIT Expat license.
- GitLab Enterprise Edition (EE) includes [extra features](https://about.gitlab.com/features/#compare) that are more useful for organizations with more than 100 users. To use EE and get official support please [become a subscriber](https://about.gitlab.com/pricing/).
Please see the [requirements documentation](doc/install/requirements.md) for system requirements and more information about the supported operating systems.
There are various other options to install GitLab, please refer to the [installation page on the GitLab website](https://about.gitlab.com/installation/) for more information.
To work on GitLab itself, we recommend setting up your development environment with [the GitLab Development Kit](https://gitlab.com/gitlab-org/gitlab-development-kit).
If you do not use the GitLab Development Kit you need to install and setup all the dependencies yourself, this is a lot of work and error prone.
One small thing you also have to do when installing it yourself is to copy the example development unicorn configuration file:
Instructions on how to start GitLab and how to run the tests can be found in the [development section of the GitLab Development Kit](https://gitlab.com/gitlab-org/gitlab-development-kit#development).
## Software stack
GitLab is a Ruby on Rails application that runs on the following software:
There are a lot of [third-party applications integrating with GitLab](https://about.gitlab.com/applications/). These include GUI Git clients, mobile applications and API wrappers for various languages.