Browser-based LaTeX editor compiles pdfTeX to PDF entirely client-side via WASM

TeXbrain shifts LaTeX compilation from local toolchains or cloud services to the browser, using a WASM port of pdfTeX. This eliminates the need for users to install LaTeX distributions, manage package dependencies, or rely on external servers. The approach mirrors recent trends in bringing traditionally desktop-bound tools to the browser, but with a focus on minimizing setup overhead. For engineers, this means immediate access to a LaTeX environment without configuring paths, package managers, or build scripts. The trade-off is compatibility: the tool only supports pdfTeX, so documents requiring XeTeX or LuaTeX features like fontspec or polyglossia will fail to compile.

The editor integrates git operations directly into the browser tab, using isomorphic-git to handle cloning, branching, and remote syncs. This is enabled by a CORS proxy, as browsers cannot natively speak the git protocol. While this simplifies version control for users, it introduces a dependency on network availability for remote operations. Local filesystem access is provided via the File System Access API, but this is currently limited to Chromium-based browsers. Users on Firefox or Safari must rely on the Origin Private File System, which may not integrate as seamlessly with their existing workflows. The git integration and filesystem access are designed to mimic a local IDE, but the browser sandbox imposes constraints that could disrupt users accustomed to CLI tools or native applications.

Package management is handled dynamically, with common packages bundled and others fetched on-demand from a TeX Live mirror. This reduces initial load time and storage requirements, as only packages used in a document are downloaded. However, the first compile of a document requiring new packages will be slower, as the browser must fetch and cache them. Subsequent compiles are faster, and the app works offline once packages are cached. The lack of bibtex or biber support is a notable limitation, as it restricts bibliography workflows to basic thebibliography environments. This may not affect simple documents but could be a dealbreaker for academic papers or theses requiring complex citation styles.

The tool is built on modern web technologies like SvelteKit, CodeMirror 6, and pdf.js, which provide a responsive and feature-rich editing experience. The use of static deployment means the app has no backend, reducing operational complexity and cost. However, this also means there is no central server to handle tasks like collaborative editing or persistent storage. For engineers, this design choice prioritizes simplicity and privacy but may limit use cases where server-side processing or real-time collaboration are necessary. The app’s reliance on browser APIs and WASM also means performance may vary across devices, particularly for large documents or complex compiles.