uPub — write books on your phone

Since this post, uPub was renamed {write} — the app is the same.

uPub is a new unifile type: a distraction-free Markdown writing app, built for phones first, that exports real e-books. (It launched under the working name "Writer".)

It is deliberately not the Markdown editor we already ship. That one is a document tool — panes, live preview, code-editor guts. uPub is a writing tool: one column of text, dimmed syntax markers, a keyboard toolbar, and nothing else on screen.

A different editor

uPub doesn't use CodeMirror. Its editor renders each source line as its own block, which buys the one typographic feature writing apps live or die by: hanging indent. When a list item wraps, the wrapped lines align under the item's text — not under the bullet. The editor font is monospaced, so the indent is character-exact, like a well-set outline.

Everything else stays plain text. What you see is the file; markers are just quieter than words.

EPUB out

Export produces a standard EPUB 3 (with an EPUB 2 fallback TOC), assembled entirely on your device: every # heading becomes a chapter, ## headings land in the reader's table of contents, front matter (title:, author:, language: …) fills the book's metadata, and a title page is generated. On iOS the share sheet hands it straight to Apple Books or Files.

Still a unifile

The rest is the unifile you know: git-style commits and restore inside the document, a .unifile.json that round-trips text plus full history, an installable offline PWA and a single-file .html shape, and a strict no-network, no-telemetry posture.

Read the full guide, or get uPub.