GitHub is an online software development platform for storing, tracking, and collaborating on software projects. The platform simplifies the sharing of code files between developers, enabling collaboration, in particular on open-source projects. GitHub also acts as a social networking site for developers to openly network and showcase their work. The platform is available for free, with paid subscriptions offering additional features. GitHub offers a range of features related to collaborative coding, automation and CI/CD, security, client apps, project management, and team administration. The company has begun offering AI-powered features, including GitHub Copilot, which provides real-time coding suggestions.
Founded in 2008 and headquartered in San Francisco, GitHub has grown to over 100 million users, including developers from 90 of the Fortune 100 companies, and over 330 million code repositories. In 2018, GitHub was acquired by Microsoft for $7.5 billion.
GitHub is named after Git, an open-source version control software for managing and tracking file revisions. The most widely used version control system for software development, GitHub leverages Git for its services. When working on a software project, multiple developers frequently update the codebase, adding features and fixing bugs, at the same time. Rather than directly changing the source code, affecting users, developers work on their own copy of the code, testing their changes before adding it to the main codebase. They typically:
- Download a copy of the source code from its central repository to their local system
- Make their modifications
- Merge new code back with the source files in the repository
- Add comments explaining the changes
Git allows developers to track these changes and store previous versions as backups. GitHub simplifies the process when multiple contributors are working on the same project. The platform provides a central repository for all of the project's code and documentation and shows how new changes will affect the main branch, catching errors before publishing. When multiple devs make changes to different parts of the project, GitHub makes it easier to see how one piece of code affects the rest of the project.
In 2005, Linus Torvalds released Git, an open-source version control system. Git enabled developers to work on the same project and track their changes, as well as "forking" or separating versions of the project into distinct branches. While Git made collaborating on open-source projects easier, it was difficult for developers to find projects to contribute to.
PJ Hyett and Chris Wanstrath began discussing ideas that would go on to become GitHub in 2007. Both programmers were working for CNET using the Ruby on Rails development framework. While working on projects at CNET, they developed improvements and suggestions to the Rails codebase but couldn't get anyone to look at their code. The Rails project was managed by a small group of coders managing contributions manually.
After seeing the potential of Git, Tom Preston-Werner, a Ruby programmer in the Bay Area, began working on a new tool that allowed coders to access Git repositories in an object-oriented manner using Ruby on Rails, called Grit. He met Wanstrath through mutual acquaintances and began discussing Grit. Preston-Werner’s goal was to create a place where entire code libraries could be hosted, and programmers could work on projects collaboratively to get the most out of Git. He called it a “Git hub.”
Preston-Werner and Wanstrath began working on the first version of GitHub on October 1, 2007. At 10:24 p.m. PST on Friday, October 19, 2007, just weeks after their first meeting, Wanstrath made the first-ever GitHub commit. The pair continued working on the first iterations of GitHub during the weekends, with Preston-Werner handling design and Wanstrath focusing on implementing Preston-Werner’s features. After three months, in January 2008, they released GitHub as a private beta. They emailed their friends to try the new tool and received positive feedback. That same month, Hyett joined as the third cofounder. In February 2008, they officially founded the company GitHub, Inc., changing its name from Logical Awesome. In April 2008, they launched the GitHub with an official website.
The platform saw rapid growth. Speaking at the Yahoo Developer Talk in February 2009, Preston-Werner stated that more than 46,000 public repositories were being hosted on GitHub. By July 2009, GitHub had more than 100,000 users and was hosting over 90,000 public repositories. This growth was achieved primarily through word-of-mouth in the software development community. On June 29, 2010, GitHub introduced its Organizations feature, a new tool that allowed corporate users to manage group-owned repositories from a single, centralized dashboard. By the end of 2011, GitHub was hosting more than 2 million repositories and had surpassed SourceForge, Google Code, and Microsoft’s CodePlex in terms of both users and commits.
In July 2012, GitHub received VC funding for the first time with a $100 million series A round from Andreessen Horowitz that valued the company at $750 million. Prior to the funding, the company was bootstrapped and profitable. At the time of the funding, the company had 100 employees and 1.7 million users working on over three million projects.
In May 2013, the White House drafted and released the official Open Data Policy of the United States on GitHub. This was the first time federal legislative policy had been shared in such a manner, with GitHub hosting governmental policy documents externally on its servers.
On July 30, 2015, GitHub raised $250 million in Series B funding led by Sequoia Capital with participation from Thrive Capital and Institutional Venture Partners also participated in this round. Reports at the time stated the round valued the company at $2 billion. In September 2015, GitHub's annual recurring revenue was approximately $90 million, a figure that rose to $140 million in August 2016. Revenue from personal plans stagnated, but the drive in revenue came from its Organizations plans, which made up half of the company's income. On June 4, 2018, Microsoft announced plans to acquire GitHub for $7.5 billion in Microsoft stock. The deal was finalized in October 2018.
In June 2021, GitHub and OpenAI launched a technical preview of a new AI tool called Copilot, which autocompletes code snippets. GitHub Copilot became generally available on June 21, 2021.