Frequently asked questions.

Reflow is a mobile reading app that turns PDF books into an adaptive reading experience. It extracts the content of your PDF, identifies its structure — chapters, sections, paragraphs, images — and rebuilds it as a book that reflows to fit your screen and your preferences.

Yes. PDF is the primary format. Rather than displaying the fixed pages, the app rebuilds the content so you can read it with your own typography and layout.

No. The app creates a separate reading presentation from your PDF. The original file itself is never edited.

Yes. Your original PDF stays exactly as it was. The adaptive book is an additional way of reading the same content.

Yes. Choose from five typefaces chosen for long-form reading: Literata, Gelasio, Inter, Atkinson Hyperlegible and OpenDyslexic.

Yes. You can also adjust line spacing, paragraph spacing, margins and alignment, choose a theme (Light, Sepia, Dark or Black), and read with page turns or in one continuous scroll.

Yes — and that is intentional. Reflow measures how your book lays out with your font, size, spacing, margins and screen, and creates reading pages from that. Larger text means more reading pages. Your position in the book is preserved to the sentence, and your original PDF is not affected.

Yes. Choose paged reading — with Slide, Cover, Turn or Fade page-turn effects — or one continuous scroll. Your choice is remembered.

Yes. Download a processed book to your device and read without an internet connection — highlights, notes, bookmarks and progress all work offline and synchronise when you reconnect. Downloaded books stay on the device until you remove them or sign out.

Yes. Reflow is designed for iPhone, iPad, Android phones and Android tablets, and the reading layout is calculated for each screen. The app currently reads in portrait orientation.

Yes. Long-press a word, extend the selection, and highlight it in one of six colours. You can recolour or delete a highlight at any time.

Yes. Attach notes to any passage. Notes stay attached to the text even when you change the typography.

Yes. Bookmarks save a reading position in the text, so they remain accurate even when the page count changes.

Yes. Search the full text of the book and jump directly to any result. Downloaded books can also be searched offline.

Yes. Pages without a text layer are recognised with optical character recognition (OCR), then rebuilt like any other book. Results depend on scan quality.

Image-based PDFs are processed with OCR. Clean, high-resolution scans work best; handwriting and heavily stylised layouts may not convert well.

Yes. When you are signed in, reading progress, bookmarks, highlights, notes and preferences can synchronise across your devices.

An account is needed. It keeps your library private and lets your books, progress and annotations sync between devices. Creating one takes a minute.

Uploaded books are processed to create your reading version and stored in your private library so you can access them. They are not shared with other users. Our Privacy Policy explains this in detail.

Yes. Your library is private to your account. We do not sell your books or your reading data.

Yes. Open a book’s page and choose Delete — it is removed along with its highlights, notes and bookmarks on all your devices. You can also delete your whole account from Profile → Account → Delete account. See the Data Deletion page for details.

Some optional features use AI: Ask the book, Explain (for a selected passage) and chapter summaries. Answers are generated only when you ask, and reading never depends on AI. Behind the scenes, AI may also help classify headings while a book is processed, and books are indexed so Ask the book can find relevant passages. AI never rewrites the author’s text — see our Privacy Policy for details.

No. The text you read is the text of your book. AI answers appear separately, only when you ask, and cite the passages they draw on.