About PhiTeX Instant for Overleaf (unofficial)
PhiTeX Instant shows a live preview of your Overleaf document that updates as you type, next to Overleaf's own PDF.
UNOFFICIAL AND EXPERIMENTAL
This extension is not made, endorsed or supported by Overleaf. "Overleaf" only names the site it works with. It is an early preview of PhiTeX, a TeX engine that keeps a document compiled as you edit it: each keystroke rebuilds only the part of the document it touched, and the page you're looking at is repainted first.
PhiTeX currently handles a subset of plain TeX and does not run LaTeX yet. On a LaTeX project the panel says so, and what it shows is not your document. Overleaf's PDF is always the real one.
FEATURES
• Instant view: a continuous, scrollable preview beside the editor, toggled with the ⚡ Instant button
• Updates on every keystroke, no Recompile needed
• Works in Overleaf's "Open PDF in separate tab" window too
• Diagnostics: missing files, undefined commands, unsupported parts
• Download PhiTeX's own PDF of the document
• Support for minted (Pygments in WebAssembly!)
PRIVACY
• Typesetting runs in your browser (WebAssembly). Your documents are never sent anywhere by us.
• The extension reads your project from overleaf.com, as you, the same way the editor does. It never writes to Overleaf or changes your documents.
• TeX packages it doesn't bundle are downloaded by name from a static copy of TeX Live's files (shelf-phitex.pages.dev). No document text or identifier is sent.
• No analytics, no accounts, no ads.
FREE SOFTWARE
GNU AGPL, version 3 only. © 2026 Ammar Seliaman. Provided as is, without any warranty.