Professional offline book-authoring and export tool for authors. Write, format, and publish print-ready books and EPUB files — entirely in the browser with no server required. Single-file HTML PWA. Pros Entirely self-contained — one HTML file, no backend, no install, works fully offline as a PWA Impressive feature depth: multiple content modes (novel, screenplay, poetry, lyrics, workbook), guided mode, accessibility panel, dyslexia font, focus-line mode Strong export range — EPUB 3, PDF (Amazon KDP), MOBI-HTML, and plain HTML from a single tool Auto-detects chapters and reflowing text; handles Word/Google Docs paste cleanup automatically Rich UI: resizable panels, zoom, snap guides, spread/single view, print preflight, track changes, image placement with rotation Privacy-respecting by design — no account, no server, no tracking; data never leaves the browserExtensive keyboard shortcuts and a guided wizard for beginners
Cons No real-time collaboration — Studio tier mentions "5-seat team sharing" but the file-centric model makes concurrent editing very difficult Font loading from Google Fonts CDN means first launch requires internet; offline mode may render with fallback fonts Image editing is minimal (resize, rotate, caption) — no cropping, filters, or colour adjustment
No comment or annotation sharing — annotations are stored locally, making editorial review workflows impossible without exporting No table of contents generation or automatic index building — users must manage front matter manually No spell-check or grammar integration — the tool handles formatting but not writing quality No footnote or endnote reflowing when text is edited — footnote positions are static No multi-book or series project management — each session is a single book
Potentials & benefits Ideal for self-publishing authors who want a professional typesetting tool without a subscription or cloud dependency The offline-first PWA model makes it viable for writers in low-connectivity environments or privacy-sensitive contexts Multi-format support (novel, screenplay, poetry, workbook) in one tool gives it a wide audience across writing disciplines Strong potential as an education tool — schools could host it as a static file with zero infrastructure cost The guided mode lowers the barrier significantly for non-technical writers who find layout tools intimidating One-time pricing is a compelling differentiator against subscription-heavy competitors (Vellum, Atticus, Reedsy) With cloud sync and DOCX export added, it could realistically become a serious competitor in the indie author tooling market
Suggestions Add optional cloud sync (end-to-end encrypted) via a companion service, while keeping local-first as the default Introduce automatic TOC and index generation from chapter headings Bundle a lightweight spell-check library (e.g. Hunspell via WASM) so writing quality help doesn't require leaving the tool Allow font embedding at export time so EPUB renders consistently without CDN dependency Add a DOCX export for editorial handoff — this would dramatically reduce friction in the publish pipeline
Modularise the codebase into separate JS/CSS files bundled at build time — the monolithic file is a long-term maintainability risk
What it is: Folio is a single-file, offline-first book authoring tool — the entire application (7,757 lines of HTML, CSS, and JS) runs in the browser with no server, no account, and no tracking. It supports novel, screenplay, poetry, lyrics, and workbook content modes, and exports to EPUB 3, PDF (KDP-ready), MOBI-HTML, and HTML. Where it shines: The privacy-first, offline architecture is genuinely rare in this space. The feature breadth — guided mode, accessibility options (dyslexia font, focus-line mode, high contrast), track changes, version snapshots, and image placement — is impressive for a single-file tool. The one-time licensing model is a strong pitch against subscription competitors like Atticus or Vellum.
realistically challenge established indie author tools in the self-publishing market.