TeXbrain is a free, open-source LaTeX editor that runs entirely in the browser, offering live PDF preview, real-time collaboration, and built-in git integration without requiring any account or backend. Created by a master's engineering student frustrated with paid features in tools like Overleaf, it compiles LaTeX to PDF client-side using WebAssembly (SwiftLaTeX) and supports direct folder access via the File System Access API. Users can manage git repositories directly in the browser using isomorphic-git, with no terminal required.

The tool works offline after initial load and includes a smart package-loading system that caches files efficiently, fetching only filenames over the network—never document content. Currently limited to pdfTeX (no XeTeX/LuaTeX), with packages pinned to TeX Live 2020 and no bibtex/biber support yet. Ideal for Chromebooks, university labs, or anyone avoiding local TeX installs.

Already used by some for thesis work, with community contributions and bug reports shaping its development.