Online E-book Reader

Those files are locked with DRM (Adobe ADEPT, Kindle, Readium LCP), and only the store’s app can read them. The reader recognizes the protection and says so plainly. An .acsm file is not a book but a ticket for Adobe Digital Editions: the book itself is downloaded in the Adobe app. DRM-free books — classics from Project Gutenberg and Wikisource, files from authors and publishers without DRM — open right away.

Press Save library: books, covers, reading positions, bookmarks, highlights, notes and stats are packed into one archive. On the other device, open this page and drop the archive onto the upload zone — the reader recognizes it and restores everything without creating duplicates. If a book is already on the shelf, the more recent position wins.

Yes, and it is worth knowing in advance. Safari on iPhone and iPad clears a site’s data if it has not been opened for 7 days — except for sites added to the Home Screen. Chrome, when the disk runs low, deletes data of sites that have no permission for persistent storage; the reader asks for it by itself after your first book. The safest habit is to save your library to an archive from time to time.

Yes. For FB2 the encoding comes from the file header; for TXT it is detected from the text itself: UTF-8, UTF-16, Windows-1251, KOI8-R and other single-byte encodings. In a TXT book the reader finds chapters by lines such as “Chapter…”, “Part…” or Roman numerals and rebuilds paragraphs even when lines were wrapped at 70 characters.

Yes. PDF and DjVu open page by page with fit-page and fit-width zoom; each page is drawn at the size of your screen, so even a 900-page scan opens right away. If the file has a text layer, you can select, highlight and search the text. CBZ, CBR and CB7 comics read like picture books. In dark themes a PDF can be inverted so white pages don’t glare at night.

At first from an average reading speed, and after a few minutes from your own: the reader counts only the time you were actually turning pages and ignores pauses longer than four minutes. The speed is remembered per book, because a textbook and a novel read differently.

All marks are stored with the library in this browser and go into the archive when you save it. The book’s list of marks opens with the pencil button; from there you can export them as one Markdown file — by chapter, with quotes and your notes — and open it in Obsidian, Notion or any text editor.