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Crossbill

Crossbill

A self-hosted reading companion. Read EPUBs in the browser or sync highlights from your e-reader. Then study them with chapter digests, flashcards, notes and reflections. Inspired by Mortimer J. Adler's How to Read a Book.
Get startedView on GitHub
Crossbill's home page: a row of recent book covers, a year of reading activity drawn as a heat map, and a timeline of the newest highlights and notes.

Home: the books you are reading, a year of reading activity, and your latest highlights and notes.

What it does

Section titled “What it does”

Web ebook reader

Upload an EPUB and read it in the browser. The reader opens where you left off on any device. Jump from a highlight to its place in the book, and make new highlights.

Sync from KOReader

Optional. The KOReader plugin uploads your highlights, highlight styles and reading sessions. Highlights you make in the web reader sync back to the device.

Organize

Group highlights and notes with your own tags, cluster those tags into tag groups, and name the labels your e-reader’s highlight styles stand for.

Write notes

Write notes about a term, a character, a concept or the gist of a chapter. Link them to the book’s chapters, highlights and tags.

Chapter digests

Generate a summary, key points and comprehension questions for a chapter. Read them before the chapter to skim it, or after it for review. Works with Ollama, OpenAI, Anthropic and Gemini.

Flashcards

Make question-and-answer cards from highlights, chapters and notes, or let the AI suggest them. Study them in Anki.

Search by meaning

Find highlights, notes and chapters by meaning, across all books and languages. Optional. Needs an embedding provider.

Book reflections

Answer Adler’s four analytical-reading questions about a book. Track how far you are with each book with a reading stage.

Crossbill is self-hosted and multi-user. Your data stays on your own server.

A closer look

Section titled “A closer look”
A book's highlights page: highlights grouped under their chapter headings, each with a date, page number and tag, with tag groups in the left sidebar and a chapter list on the right.

A book’s highlights, grouped by chapter. Filter by tag, date or highlight style, search the book, or jump to a chapter.

A book's structure page: the table of contents as a nested tree, each chapter marked read, reading or unread, with a one-line gist and counts of its highlights and notes.

The book’s structure: its table of contents, what you have read, a one-line gist per chapter, and the highlights and notes of each chapter.

A chapter dialog: a gist, a generated chapter summary with key points, and comprehension questions with the reader's own written answers below each.

A chapter digest: summary, key points and questions to think about while reading. You can write your answers below each question.

The web reader showing chapter X of Frankenstein in the browser: two passages highlighted in place, one in pink and one in orange, the book's title and a contents button in the top bar, page-turn arrows at either edge, and pages left in the chapter and percent read in the footer.

The web reader shows your highlights in their colours. Select a passage to highlight it.

The ecosystem

Section titled “The ecosystem”
KOReader pluginOptional. Syncs highlights, highlight styles and reading sessions from your e-reader, and pulls chapter digests back down to it.
Obsidian pluginBrings your highlights into your Obsidian vault.
Anki add-onSyncs the flashcards you made in Crossbill into your Anki collection.
MCP serverLets Claude and other AI assistants read and work with your library.
Docker imagetumetsu/crossbill, the image the sample docker compose setup runs.