Cloud DevOps Software Engineering


Font Awesome 5 brands github.svg
GitHub logo 2013.svg
Type of businessSubsidiary
Type of siteCollaborative version control
Available inEnglish
FoundedFebruary 8, 2008; 13 years ago (as Logical Awesome LLC)
HeadquartersSan Francisco, California, United States
Area servedWorldwide
Founder(s)Tom Preston-WernerChris WanstrathP. J. HyettScott Chacon
CEONat Friedman
Key peopleMike Taylor (CFO)
IndustryCollaborative version control (GitHub)
Blog host (GitHub Pages)
Package repository (NPM)
RegistrationOptional (required for creating and joining repositories)
Users56 million (Sep 2020)
LaunchedApril 10, 2008; 12 years ago
Current statusActive
Written inRuby
C [2]

GitHub, Inc. is a provider of Internet hosting for software development and version control using Git. It offers the distributed version control and source code management (SCM) functionality of Git, plus its own features. It provides access control and several collaboration features such as bug trackingfeature requests, task managementcontinuous integration and wikis for every project.[3] Headquartered in California, it has been a subsidiary of Microsoft since 2018.[4]

GitHub offers its basic services free of charge. Its more advanced professional and enterprise services are commercial.[5] Free GitHub accounts are commonly used to host open-source projects.[6] As of January 2019, GitHub offers unlimited private repositories to all plans, including free accounts, but allowed only up to three collaborators per repository for free.[7] Starting from April 15, 2020, the free plan allows unlimited collaborators, but restricts private repositories to 2,000 minutes of GitHub Actions[8] per month.[9] As of January 2020, GitHub reports having over 40 million users[10] and more than 190 million repositories[11] (including at least 28 million public repositories),[12] making it the largest host of source code in the world.[13]


GitHub at AWS Summit

The GitHub service was developed by Chris WanstrathP. J. HyettTom Preston-Werner and Scott Chacon using Ruby on Rails, and started in February 2008. The company, GitHub, Inc., has existed since 2007 and is located in San Francisco.[14]The shading of the map illustrates the number of users as a proportion of each country’s Internet population. The circular charts surrounding the two hemispheres depict the total number of GitHub users (left) and commits (right) per country.

On February 24, 2009, GitHub announced 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. At that time, about 6,200 repositories had been forked at least once and 4,600 had been merged.

That same year, the site was harnessed by over 100,000 users, according to Github, and had grown to host 90,000 unique public repositories, 12,000 having been forked at least once, for a total of 135,000 repositories.[15]

In 2010, GitHub was hosting 1 million repositories.[16] A year later, this number doubled.[17] ReadWriteWeb reported that GitHub had surpassed SourceForge and Google Code in total number of commits for the period of January to May 2011.[18] On January 16, 2013, GitHub passed the 3 million users mark and was then hosting more than 5 million repositories.[19] By the end of the year, the number of repositories were twice as much, reaching 10 million repositories.[20]

In 2012, GitHub raised $100 million in funding from Andreessen Horowitz with $750 million valuation.[21] Peter Levine, general partner at Andreessen Horowitz, stated that GitHub had been growing revenue at 300% annually since 2008 “profitably nearly the entire way”.[22] On July 29, 2015, GitHub stated it had raised $250 million in funding in a round led by Sequoia Capital. Other investors of that round included Andreessen Horowitz, Thrive Capital, and IVP (Institutional Venture Partners).[23] The round valued the company at approximately $2 billion.[24]

In 2015, GitHub opened an office in Japan that is its first office outside of the U.S.[25] In 2016, GitHub was ranked No. 14 on the Forbes Cloud 100 list.[26] It has not been featured on the 2018, 2019 and 2020 lists.[27]

On February 28, 2018, GitHub fell victim to the third largest distributed denial-of-service (DDoS) attack in history, with incoming traffic reaching a peak of about 1.35 terabits per second.[28]

On June 19, 2018, GitHub expanded its GitHub Education by offering free education bundles to all schools.[29][30]

Acquisition by Microsoft

From 2012 Microsoft became a significant user of GitHub, using it to host open-source projects and development tools such as .NET CoreChakra CoreMSBuildPowerShellPowerToysVisual Studio CodeWindows CalculatorWindows Terminal and the bulk of its product documentation (now to be found on Microsoft Docs).[31][32]

On June 4, 2018, Microsoft announced its intent to acquire GitHub for US$7.5 billion. The deal closed on October 26, 2018.[33] GitHub continued to operate independently as a community, platform and business.[34] Under Microsoft, the service was led by Xamarin‘s Nat Friedman, reporting to Scott Guthrie, executive vice president of Microsoft Cloud and AI. GitHub’s CEO, Chris Wanstrath, was retained as a “technical fellow”, also reporting to Guthrie.

There have been concerns from developers Kyle Simpson, JavaScript trainer and author, and Rafael Laguna, CEO at Open-Xchange over Microsoft’s purchase, citing uneasiness over Microsoft’s handling of previous acquisitions, such as Nokia’s mobile business or Skype.[35][36]

This acquisition was in line with Microsoft’s business strategy under CEO Satya Nadella, which has seen a larger focus on the cloud computing services, alongside development of and contributions to open-source software.[37][4][32] Harvard Business Review argued that Microsoft was intending to acquire GitHub to get access to its user base, so it can be used as a loss leader to encourage use of its other development products and services.[38]

Concerns over the sale bolstered interest in competitors: Bitbucket (owned by Atlassian), GitLab (a commercial open source product that also runs a hosted service version) and SourceForge (owned by BIZX, LLC) reported that they had seen spikes in new users intending to migrate projects from GitHub to their respective services.[39][40][41][42]

In September 2019, GitHub acquired Semmle, a code analysis tool.[43] In February 2020, GitHub launched in India under the name GitHub India Private Limited.[44] In March 2020, GitHub announced that they were acquiring npm, a JavaScript packaging vendor, for an undisclosed sum of money.[45] The deal was closed on 15 April 2020.[46]

In early July 2020, the GitHub Archive Program was established, to archive its open source code in perpetuity.[47]


Development of the platform began on October 19, 2007.[60][61][62] 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.[63]

Projects on can be accessed and managed using the standard Git command-line interface; all standard Git commands work with it. also allows users to browse public repositories on the site. Multiple desktop clients and Git plugins are also available. The site provides social networking-like functions such as feeds, followers, wikis (using wiki software called Gollum) and a social network graph to display how developers work on their versions (“forks“) of a repository and what fork (and branch within that fork) is newest.

Anyone can browse and download public repositories but only registered users can contribute content to repositories. With a registered user account, users are able to have discussions, manage repositories, submit contributions to others’ repositories, and review changes to code. began offering unlimited private repositories at no cost in January 2019 (limited to three contributors per project). Previously, only public repositories were free.[64][65][66] On April 14, 2020, GitHub made “all of the core GitHub features” free for everyone, including “private repositories with unlimited collaborators”.[67]

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,[68] Hyett, and Preston-Werner.


The main purpose of is to facilitate the version control and issue tracking aspects of software development. Labels, milestones, responsibility assignment, and a search engine are available for issue tracking. For version control, Git (and by extension allows pull requests to propose changes to the source code. Users with the ability to review the proposed changes can see a diff of the requested changes and approve them. In Git terminology, this action is called “committing” and one instance of it is a “commit”. A history of all commits are kept and can be viewed at a later time.

In addition, GitHub supports the following formats and features:

  • Documentation, including automatically rendered README files in a variety of Markdown-like file formats (see README § On GitHub)
  • Wikis
  • GitHub Actions, which allows building continuous integration and continuous deployment pipelines for testing, releasing and deploying software without the use of third-party websites/platforms
  • Graphs: pulse, contributors, commits, code frequency, punch card, network, members
  • Integrations Directory[69]
  • Email notifications
  • Discussions
  • Option to subscribe someone to notifications by @ mentioning them.[70]
  • Emojis[71]
  • Nested task-lists within files
  • Visualization of geospatial data
  • 3D render files that can be previewed using a new integrated STL file viewer that displays the files on a “3D canvas”.[72] The viewer is powered by WebGL and Three.js.
  • Photoshop’s native PSD format can be previewed and compared to previous versions of the same file.
  • PDF document viewer
  • Security Alerts of known Common Vulnerabilities and Exposures in different packages

GitHub’s Terms of Service do not require public software projects hosted on GitHub to meet the Open Source Definition. The terms of service state, “By setting your repositories to be viewed publicly, you agree to allow others to view and fork your repositories.”[73]

GitHub Enterprise

GitHub Enterprise is a self-managed version of with similar functionality. It can be run on an organization’s own hardware or on a cloud provider, and it has been available since November 2011.[74] In November 2020, source code for GitHub Enterprise Server was leaked online in apparent protest against DMCA takedown of YouTube-dl. According to GitHub, the source code came from GitHub accidentally sharing the code with Enterprise customers themselves, not from an attack on GitHub servers.[75][76]

GitHub Pages

GitHub Pages is a static web hosting service offered by GitHub since 2008 to GitHub users for hosting user blogs, project documentation,[77][78] or even whole books created as a page.[79]

All GitHub Pages content is stored in a 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.[80]

As with the rest of GitHub, it includes both free and paid tiers of service, instead of being supported by web advertising. Web sites generated through this service are hosted either as subdomains of the domain, or as custom domains bought through a third-party domain name registrar.[81] When custom domain is set on a GitHub Pages repo a Let’s Encrypt certificate for it is generated automatically. Once the certificate has been generated Enforce HTTPS can be set for the repository’s website to transparently redirect all HTTP requests to HTTPS.[82][83]


GitHub also operates other services: a pastebin-style site called Gist[63] that is for hosting code snippets (GitHub proper is for hosting larger projects).

Tom Preston-Werner presented the then-new Gist feature at a punk rock Ruby conference in 2008.[84] Gist builds on the traditional simple concept of a pastebin by adding version control for code snippets, easy forking, and TLS encryption for private pastes. Because each “gist” has its own Git repository, multiple code snippets can be contained in a single paste and they can be pushed and pulled using Git. Further, forked code can be pushed back to the original author in the form of a patch, so gists (pastes) can become more like mini-projects.[citation needed]

Before February 18, 2018, unregistered users were able to upload text to the site. Since then, uploading gists has been deactivated for unregistered users with the aim to mitigate spamming.[85]

Education program

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 BitnamiCrowdflowerDigitalOceanDNSimpleHackHandsNamecheap, Orchestrate, Screenhero, SendGridStripeTravis CI and Unreal Engine to launch the program.[86]

In 2016 GitHub announced the launch of the GitHub Campus Experts program[87] to train and encourage students to grow technology communities at their universities. The Campus Experts program is open to university students of 18 years and older across the world.[88] GitHub Campus Experts are one of the primary ways that GitHub funds student oriented events and communities, Campus Experts are given access to training, funding, and additional resources to run events and grow their communities. To become a Campus Expert applicants must complete an online training course consisting of multiple modules designed to grow community leadership skills.

GitHub Marketplace service

GitHub also provides some software as a service integrations for adding extra features to projects. Those services include:

  • Project management for software teams. Automatically see pull requests, automated builds, reviews, and deployments across all of your repositories in GitHub.
  • Rollbar: Integrate with GitHub to provide real time debugging tools and full-stack exception reporting. It is compatible with all well used code languages, such as JavaScriptPython.NETRubyPHPNode.jsAndroidiOSGoJava, and C#.
  • Codebeat: For automated code analysis specialized in web and mobile developers. The supported languages for this software are: ElixirGoJavaSwiftJavaScriptPythonRubyKotlinObjective-C, and TypeScript.
  • Travis CI: To provide confidence for your apps while doing test and ship. Also gives full control over the build environment, to adapt it to the code. Supported languages: GoJavaJavaScriptObjective-CPythonPHPRuby, and Swift.
  • GitLocalize: Developed for teams that are translating their content from one point to another. GitLocalize automatically syncs with your repository so you can keep your workflow on GitHub. It also keeps you updated on what needs to be translated.

GitHub Sponsors

GitHub Sponsors allows users to make monthly money donations to projects hosted on GitHub.[89] 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.[90][91]

GitHub Archive Program

In July 2020, GitHub stored a February archive of the site[47] in an abandoned mountain mine in Svalbard, Norway, part of the Arctic World Archive and not far from the Svalbard Global Seed Vault. The archive contained the code of all active public repositories, as well as that of dormant, but significant public repositories. The 21TB of data was stored on piqlFilm archival film reels as QR codes, and is expected to last 500–1,000 years.[92][93][94][95]

The GitHub Archive Program is also working with partners on Project Silica, in an attempt to store all public repositories for 10,000 years. It aims to write archives into the molecular structure of quartz glass platters, using a high-precision laser that pulses a quadrillion (1,000,000,000,000,000) times per second.[95]

Developed projects

  • Atom, a free and open-source text and source code editor
  • Electron, an open-source framework to use JavaScript-based websites as desktop applications.

Prominent users

Some prominent open source organizations and projects use GitHub as a primary place for collaboration, including:

See also


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