Read EPUB eBooks in your browser with adjustable fonts, themes, and bookmarks.
Drop an .epub file onto the page and the reader unpacks it entirely in the browser, then renders the book as paginated, reflowable text you can adjust with font, theme, and bookmark controls. An EPUB is a ZIP archive of HTML and CSS pages, and the reader follows the package document's spine - the declared reading order - to move chapter by chapter. Nothing is uploaded; the file never leaves your machine. The common surprise: EPUBs purchased from bookstores are usually DRM-encrypted and will not open, and fixed-layout books (comics, spreads, wide tables) refuse to reflow cleanly into a single reading column.
A concrete input and expected output from the current implementation.
Input
A minimal EPUB with two files in the archive: META-INF/container.xml: <container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container"><rootfiles><rootfile full-path="OEBPS/content.opf" media-type="application/oebps-package+xml"/></rootfiles></container> OEBPS/content.opf: a package document whose manifest lists chapter1.xhtml and whose spine contains one itemref, idref="c1", pointing at it
Expected output
The reader opens at page 1 showing chapter1.xhtml: its title and body text rendered with the current font size and theme. The page, bookmark, and chapter controls now act on that single chapter, and no other content is shown because the spine declares nothing else.
The reader starts from container.xml, follows the rootfile path to the package document, then renders the spine's first itemref. That resolution chain decides everything displayed, which is why a corrupt or missing container.xml produces an immediate error with no partial page.
An EPUB is a ZIP container. Reading starts at META-INF/container.xml, whose rootfile entry points to the package document, content.opf. That file's manifest names every resource in the book and its spine lists the content documents in reading order. The reader renders the spine's first document first; malformed archives fail at this resolution step, before any page is drawn.
Each content document is laid out to the current viewport and split into pages; changing font size or theme re-paginates the whole book, so the page count shifts. A bookmark stores the chapter and the position inside it, and bookmarks and settings persist in browser storage, so a later visit restores your place without re-finding it.
The most common cause is DRM. Many stores ship EPUBs encrypted to your account, and a browser reader has no way to decrypt them. Try a DRM-free copy - many publishers offer one, and files you export from editing tools always open - and if that works, the file itself was fine.
Yes, if you return to the same site in the same browser. Bookmarks and settings live in the browser's local storage, not on a server, so a later session restores them. Clearing site data, private browsing, or switching browsers loses them, so do that only when you are ready to start over.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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