Microsoft announced the acquisition of GitHub on June 4, 2018, for approximately $7.5 billion in Microsoft stock. The deal closed on October 26, 2018, following regulatory approval. GitHub became a subsidiary of Microsoft, retaining its brand and leadership (CEO Nat Friedman, who replaced Chris Wanstrath).
Historical Context: Microsoft and Open Source
The acquisition was remarkable given Microsoft's history. In the late 1990s and early 2000s, Microsoft was the FOSS movement's most visible corporate adversary:
By 2018, Microsoft had undergone a documented transformation under CEO Satya Nadella (appointed 2014). The company had open-sourced .NET (2014), Visual Studio Code (2015, which became the dominant code editor), and PowerShell; joined the Linux Foundation; contributed to Linux and other FOSS projects; and declared "Microsoft loves Linux." The GitHub acquisition was the most visible expression of this reversal.
Community Response
The community response was sharply divided. Those who trusted Microsoft's transformation saw the acquisition as validation — a recognition that GitHub and the FOSS ecosystem it supported had become indispensable. Skeptics saw it as exactly the problem FOSS critics had long warned about: critical open source infrastructure concentrated in corporate hands with no community governance.
In the days following the announcement, GitLab reported a surge in migrations from GitHub — over 100,000 new repositories imported in a 24-hour period (this figure is from GitLab's own reporting and should be treated as approximate). Gitea and other self-hosted alternatives also gained attention. The migrations represented a small fraction of GitHub's overall activity, and most developers remained on GitHub.
What the Acquisition Revealed
The acquisition highlighted a structural problem that predated it: the FOSS movement had built its primary collaboration infrastructure on a proprietary, commercially-owned platform. GitHub had never been open source software governed by the community it served — it was a for-profit company providing a service. The Microsoft acquisition made this dependency legible by changing the owner to a company with a documented history of FOSS hostility.
The concern was not merely ideological. Practically: GitHub's terms of service decisions (including the Copilot training data controversy), its compliance with government requests, its decisions about what projects to host or remove, and its strategic priorities are now made by a public company accountable to Microsoft shareholders — not to the FOSS community.
Microsoft's Subsequent FOSS Role
Post-acquisition, Microsoft has continued GitHub's operations and expanded investment. GitHub Actions (CI/CD integration), GitHub Copilot (AI code assistance), and GitHub Codespaces (cloud development environments) were launched or expanded under Microsoft ownership. GitHub Copilot's use of FOSS-licensed training data generated the most significant controversy — described under xz-backdoor-2024 era context and the modern-foss-and-sustainability-crisis-2015-present AI/ML tensions.
Microsoft became, by some metrics (GitHub contribution data), one of the largest contributors to open source software in the world. The "Halloween Documents" era of explicit FOSS hostility appears genuinely over. Whether the current posture represents a durable cultural shift or a strategic alignment that could reverse under different business conditions remains an open question.
Relationship to the Sustainability Era
The Microsoft/GitHub acquisition belongs to the modern-foss-and-sustainability-crisis-2015-present era as a case study in the governance of FOSS infrastructure. It did not resolve the sustainability problem — if anything, it intensified awareness of how dependent the FOSS ecosystem is on corporate decisions made outside any community governance process.