Y Combinator highlights 153 open source startups across its portfolio, ranging from public companies to early stage teams with as few as 1 employees. The collection spans long-standing names like GitLab, which positions itself as a single application for the entire DevOps lifecycle, alongside new entrants in areas such as coding agents, edge deployments, and open source platforms for artificial intelligence applications. Many of these companies emphasize self-hosting, enterprise readiness, and data control, reflecting growing demand for open and auditable software stacks.
Developer tools and infrastructure dominate the list, with startups like GitLab, Sourcebot, Pangolin, Better Auth, Corsair, RecipeUI, and ParadeDB targeting code collaboration, search, security, integrations, and databases. GitLab claims its approach can make the software lifecycle 200% faster, serving more than 100,000 organizations from startups to global enterprises. Sourcebot offers an open source code understanding platform already used by thousands of engineers at companies including NVIDIA, Red Hat, Wikimedia, and Arista Networks. ParadeDB presents an open source, ACID-compliant search and analytics database built on Postgres for update-heavy workloads, while Pangolin delivers identity-based remote access using WireGuard.
Artificial Intelligence and automation form another major cluster, with companies building agents, evaluation tools, and orchestration layers on open source foundations. Unsloth reports over 10 million monthly model downloads and 40K GitHub stars as it focuses on helping builders create custom models 30x faster with 90% less memory use. Browser Use calls itself the biggest open source web agent project and notes it got 40k stars in the last 3 months. Confident AI builds on the DeepEval project, which it cites as having 12.6k stars and >3m monthly downloads, to provide benchmarking and guardrails for large language model applications. Newer efforts such as Manaflow’s cmux, OpenFoundry, Klavis AI, and nCompass aim to standardize infrastructure for coding agents, open source artificial intelligence stacks, and model deployment. Across security-focused tools like Velum Labs, Tesseral, Superagent, and Hatchet, and collaboration platforms such as Mattermost and Onyx, the common thread is using open source to give enterprises more control over their workflows, data, and Artificial Intelligence systems.
