tgrep is a trigram-indexed grep tool using a client/server architecture to pre-build an index for regex search in large codebases, reaching up to 52x speedup over ripgrep on repos with 300K+ files.

It runs a persistent TCP server with a hybrid index (mmap'd on-disk trigram table plus in-memory overlay), parallel rayon search, and background indexing that serves queries immediately during builds. Microsoft integrates tgrep into GitHub Copilot CLI to power fast grep across large repositories.