Flow Reader
English · 简体中文
Flow Reader is a fast, smooth, and lightweight desktop reader for EPUB and TXT. It is built for long, uninterrupted reading: the book stays visually dominant, the interface remains compact, and frequent actions respond immediately without breaking concentration.
Hold down an arrow key and every page turn keeps up; switch rapidly between tabs again and again, and every book is ready immediately. Full-book search returns results in milliseconds even across millions of characters. Even with more than 1,200 books in the library and many books open, the app stays smooth and memory use remains restrained.
- The library and every open book stay in one compact, tabbed window. Switch between them without opening extra windows or waiting for a reading view to reopen.
- Each book retains its exact page and layout while inactive. Tabs can be reordered by dragging or keyboard shortcut and are ready the moment you return.
- Page content, chapter context, page number, and progress remain synchronized through rapid page turns, resizing, sidebar changes, and display adjustments.
- The maintained EPUB engine handles EPUB 2 and EPUB 3 navigation, reflowable and fixed-layout books, left-to-right and right-to-left reading order, and traditional vertical Chinese and Japanese text.
- Responsive single- and double-page views preserve page order, fixed-page placement, and the exact reading position as the reading area changes.
- Import repairs broken navigation and spine metadata, splits oversized single-file chapters, restores missing fixed-layout dimensions, and handles embedded fonts and archive paths that would otherwise fail on desktop.
- Bring an entire collection in at once by finding EPUB and TXT books across nested folders and turning the existing folder structure into library tags.
- Turn plain-text files into structured books with automatic encoding detection, titles and authors derived from filenames, and tailored rules for recognizing volumes and chapters.
- Select text once to copy it, search the book, open a dictionary, translate, add a highlight and note, or mark a term so every occurrence is highlighted throughout the book.
- Search the complete book or use chapter find for the current section. Results open directly at the matching text.
- Combine online lookup with local StarDict and MDict dictionaries, listen with available system voices, and switch between Google and Azure translation without leaving the page.
- The Gallery filters common decorative and duplicate images by default, while keeping every image available with preview, zoom, fit, rotation controls and download.
- Highlights and notes remain useful beyond the page: organize them, export them as readable Markdown or structured JSON, and follow links back to the exact passages in the book.
- EPUBs stay fast without forcing a choice between speed and disk space, and remain just as smooth when edited in place. Correct EPUB or TXT text directly on the page, keep reading, and export the revised book when ready.
- Built for large collections: tested with more than 1,200 books, the bookshelf stays fast while browsing, searching, filtering, and sorting.
- Combine title search with reading status, author, and tag filters; pin frequent filters, then update tags or reading status—or delete books—across the filtered results in batches.
- Start with a range of carefully balanced light and dark theme presets, or create your own from the background and accent colors. Changes appear immediately in the app and a live interface preview, making themes quick to compare and switch.
- Body-aware typography identifies the main reading text before applying font, size, weight, line height, indentation, and alignment. Distinctive typefaces, chapter headings, and other intentionally styled elements retain their character, so a carefully typeset book can be refined without flattening the publisher's design.
- Choose default page view and alignment, then adjust them for each book alongside zoom and unframed, card, book, or divider page appearances.
- Fullscreen and Zen mode remove the remaining interface when only the book matters.
src/- React frontend, including the library, reader, and settingssrc-tauri/- Tauri shell, native commands, storage, import, and searchpackages/epub-engine/- internal EPUB rendering enginecrates/- shared EPUB cover and thumbnail librariesnative/shell-thumbnails/- Windows and macOS EPUB thumbnail integrationscripts/- build, packaging, and release utilitiestests/- unit and browser integration tests
pnpm installInstall the Chromium and WebKit binaries used by the browser integration tests:
pnpm exec playwright install chromium webkitpnpm tauri:devRun the source checks and production frontend build:
pnpm checkRun an individual test layer:
pnpm test:unit
pnpm test:integrationRun one integration spec:
pnpm test:integration tests/integration/app-shell.spec.tsIntegration tests run in both the Chromium and WebKit projects by default. Run one engine explicitly when iterating on a focused failure:
pnpm test:integration:chromium tests/integration/app-shell.spec.ts
pnpm test:integration:webkit tests/integration/app-shell.spec.tsRun one integration test by matching its title:
pnpm test:integration tests/integration/app-shell.spec.ts -g "loads without client exceptions"Run the complete browser, EPUB engine, and native quality and test suite:
pnpm check:fullBuild the application without creating a distributable package:
pnpm tauri:buildBuild the complete local-use package for the current platform. The result is moved to release/:
pnpm bundle:windows:installed
pnpm bundle:macos:installed
pnpm bundle:linux:installedWindows produces an NSIS installer, macOS produces the application bundle, and Linux produces an AppImage.
Flow Reader is licensed under the GNU Affero General Public License v3.0.