Sourcebot is an open-source code understanding platform that helps both humans and AI agents make sense of massive codebases. It lets developers and AI agents search across millions of lines of code instantly and ask questions spanning multiple repositories using reasoning models. The platform is used by engineers at companies including NVIDIA, Red Hat, Wikimedia, and Arista Networks. Sourcebot was founded in 2024 and is part of Y Combinator's Fall 2025 batch.