GitHub is the center of gravity for open source - not just git hosting, but pull requests, issues, Actions, and a social graph that is effectively the public face of a project. For collaboration and visibility there is no real substitute, and that is worth being honest about: leaving does not replicate its network. What it can replicate is the hosting. Some teams simply want their repositories on their own infrastructure - to keep private code off a Microsoft-owned platform, to avoid usage tiers and outages outside their control, or to run a lightweight forge without a heavy deployment.
The open source alternative below is a self-hosted git server in that spirit: repositories, pull requests, issues, and a familiar web UI, running from a single modest binary on hardware you control. It won't hand you GitHub's audience or ecosystem, but for hosting and reviewing code on your own terms - fast to stand up, cheap to run, fully yours - it covers the part that actually has to be self-hosted.
Gitea is a self-hosted Git service for teams that want to run their own software development platform. It brings Git hosting, code review, team collaboration, a package registry, and CI/CD together in one place, aiming to be the easiest, fastest, and most painless way to set up a self-hosted Git server.
Gogs is a self-hosted Git service for hosting repositories, users, organizations, and collaboration workflows on infrastructure you control. It aims to be simple, stable, extensible, and easy to set up, using independent Go binary distributions across platforms Go supports, including Linux, macOS, Windows, and ARM-based systems.
OneDev is a Git server for teams that want code hosting, CI/CD, issue tracking, Kanban, and packages in one self-hosted DevOps platform. It supports pull requests, code review, project organization, and service desk workflows that link emails with issues.
