In the late 2000s, I was working at Borland, the formerly high-flying software development tools company. My boss and I would regularly sit around tossing out ideas for new products. The Internet was really hitting its stride, and we saw numerous opportunities. 

It seemed everyone was joining an interesting new site called “Facebook,” and we came up with the idea of “Facebook for Developers.” The idea was that you could combine a code sharing site, like SourceForge, with a social network of developers, so they could rate your code and maybe even find a way to collaborate.

The idea was quickly shot down by upper management as “not our lane.” Of course, we were basically talking about GitHub, which was launched soon afterward.

From code sharing to collaboration

Open-source software was gaining traction, and SourceForge—then the favorite place for sharing code—was based on Subversion, an old server-based source control system. Sharing code was straightforward, but collaborating on that code was not at all easy. If you had a bug fix or a new feature to add to a project, you had to email a patch to the author and hope that they applied it. Branching and merging were challenging, so the original author had to do all the work of integrating changes. The burden was on the repository owner, and the whole process was awkward.

Git and GitHub changed all that. Because Git is a distributed system, branching and merging became very easy. However, integrating those changes still required a lot of manual work by the repository owner. That’s where GitHub comes in.

It was the folks at GitHub who changed open source forever by creating the pull request. Pull requests allow a contributing developer to fork a repository, create a branch with their fixes or improvements, and open a request with the repository owner, proposing that the changes be merged. The pull request also provides a means for easily discussing, reviewing, and integrating that change with a smooth workflow. 

Open source would never be the same. Pull requests quickly became the de facto standard for collaborating on an open source project, and developers were off to the races. By 2012, GitHub had over a million users and hosted as many repositories. The platform quickly dwarfed SourceForge and became the hosting platform of choice for the developer community. GitHub eventually sold to Microsoft for $7.5 billion.

The keys that unlocked open source

GitHub’s explosive growth and ultimate triumph were driven by three innovations that made open source a viable and thus popular development model. 

First, as discussed above, GitHub provided a low-friction contribution model. This was really the catalyst that launched the open source age. The workflows were clear and understood by all. Developers could see a problem and very easily contribute a fix. They could add whole new features, and repository owners could smoothly integrate all those changes. Once the barriers were removed, there was no reason not to collaborate and contribute. 

Second, GitHub provided easy discoverability and a network effect that allowed projects to become popular very quickly. README pages made it fast and easy for a developer to describe their project. Forks and stars showed which projects were gaining popularity and proving useful. Activity was easily tracked, and lively repositories could be identified. As more developers joined and contributed, the virtuous cycle of the network effect took hold. Suddenly code was appearing everywhere, bugs were being fixed, and popular projects were becoming de facto standards. 

Third, GitHub provided a social network for developers. Thanks to profile pages, contribution graphs, and easily searchable histories, developers were able to establish a professional history and reputation online. A developer’s resume wasn’t complete without a link to their GitHub profile. Open source contributions became an easy way for early-career developers to establish themselves and demonstrate experience and skills when job seeking. A developer without a GitHub page became like a designer without a portfolio. 

A new model for development

Open source started as a fledgling movement with scattered repositories and ad hoc collaborative processes. The development of Git, a distributed source control system, and the arrival of GitHub, which harnessed Git and unleashed its power, moved open source from a minor developer subculture to the dominant model for building software that it is today. Without GitHub, there very likely wouldn’t be projects like Node.js, React, and Kubernetes.

The invention of Git gave developers the tool they needed to more easily collaborate. GitHub used that tool to give developers the platform they needed to change how software was built.