The fundamental software that underpins GitHub is Git itself, written by Linus Torvalds, creator of Linux. The additional software that provides the GitHub user interface was written using Ruby on Rails and Erlang by GitHub, Inc. developers Wanstrath, Hyett, and Preston-Werner.
Development of the GitHub platform began on October 19, 2007. The site was launched in April 2008 by Tom Preston-Werner, Chris Wanstrath, P. J. Hyett and Scott Chacon after it had been made available for a few months prior as a beta release.
Projects on GitHub can be accessed and manipulated using the standard Git command-line interface and all of the standard Git commands work with it. GitHub also allows registered and unregistered users to browse public repositories on the site. Multiple desktop clients and Git plugins have also been created by GitHub and other third parties that integrate with the platform.
A user must create an account in order to contribute content to the site, but public repositories can be browsed and downloaded by anyone. With a registered user account, users are able to have discussions, manage repositories, submit contributions to others' repositories, and review changes to code. GitHub began offering unlimited private repositories at no cost in January 2019 (limited to three contributors per project). Previously, only public repositories were free.
All GitHub Pages content is stored in Git repository, either as files served to visitors verbatim or in Markdown format. GitHub is seamlessly integrated with Jekyll static web site and blog generator and GitHub continuous integration pipelines. Each time the content source is updated, Jekyll regenerates the website and automatically serves it via GitHub Pages infrastructure.
GitHub Sponsors allows users to make monthly money donations to projects hosted on GitHub. The public beta was announced on May 23, 2019 and currently the project accepts wait list registrations. The Verge said that GitHub Sponsors "works exactly like Patreon" because "developers can offer various funding tiers that come with different perks, and they’ll receive recurring payments from supporters who want to access them and encourage their work" except with "zero fees to use the program". Furthermore, GitHub offer incentives for early adopters during the first year: it pledges to cover payment processing costs, and match sponsorship payments up to $5,000 per developer. Furthermore, users still can use other similar services like Patreon and Open Collective and link to their own websites.
GitHub Pages is a static web hosting service offered by GitHub since 2008 to GitHub users for hosting user blogs, project documentation, or even whole books created as a page.
GitHub Enterprise is a self-managed version of GitHub with similar functionality. It can be run on an organisation's own hardware or on a cloud provider, and it has been available since November 2011.
GitHub maintains a community forum where users can ask questions publicly or answer questions of other users.
GitHub is mostly used for code.
On July 5, 2009, GitHub announced that the site was being harnessed by over 100,000 users. On July 27, 2009, in another talk delivered at Yahoo!, Preston-Werner announced that GitHub had grown to host 90,000 unique public repositories, 12,000 having been forked at least once, for a total of 135,000 repositories.
In June 2015, GitHub opened an office in Japan that is its first office outside of the U.S.
On December 31, 2014, GitHub was blocked in India (along with 31 other websites) over pro-ISIS content posted by users. On January 10, 2015, GitHub was unblocked.
On July 9, 2012, Peter Levine, general partner at GitHub investor Andreessen Horowitz, stated that GitHub had been growing revenue at 300% annually since 2008 "profitably nearly the entire way".
On February 24, 2009, GitHub team members announced, in a talk at Yahoo! headquarters, that within the first year of being online, GitHub had accumulated over 46,000 public repositories, 17,000 of which were formed in the previous month alone. At that time, about 6,200 repositories had been forked at least once and 4,600 had been merged.
GitHub became interested in Oxley's work after Twitter selected a bird that he designed for their own logo. The illustration GitHub chose was a character that Oxley had named Octopuss. Since GitHub wanted Octopuss for their logo (a use that the iStock license disallows), they negotiated with Oxley to buy exclusive rights to the image.
GitHub renamed Octopuss to Octocat, and trademarked the character along with the new name. Later, GitHub hired illustrator Cameron McEfee to adapt Octocat for different purposes on the website and promotional materials; McEfee and various GitHub users have since created hundreds of variations of the character, which are available on The Octodex.
GitHub.com was a bootstrapped start-up business, which in its first years provided enough revenue to be funded solely by its three founders and start taking on employees. In July 2012, four years after the company was founded, Andreessen Horowitz invested $100 million in venture capital. In July 2015 GitHub raised another $250 million of venture capital in a series B round. Investors were Sequoia Capital, Andreessen Horowitz, Thrive Capital and other venture capital funds. As of August 2016, GitHub was making $140 million in Annual Recurring Revenue.
On March 26, 2015, GitHub fell victim to a massive DDoS attack that lasted for more than 118 hours. The attack, which appeared to originate from China, primarily targeted GitHub-hosted user content describing methods of circumventing Internet censorship.
GitHub launched a new program called the GitHub Student Developer Pack to give students free access to popular development tools and services. GitHub partnered with Bitnami, Crowdflower, DigitalOcean, DNSimple, HackHands, Namecheap, Orchestrate, Screenhero, SendGrid, Stripe, Travis CI and Unreal Engine to launch the program.