Question 1

What is an EPUB file?

Accepted Answer

EPUB is the open standard ebook format. It's a ZIP archive containing XHTML chapters, images, stylesheets, and an OPF manifest that lists every piece of content plus a NCX/NAV table of contents. Every major ebook store sells EPUBs and most libraries lend them.

Question 2

How does this reader work?

Accepted Answer

We parse the EPUB (ZIP) structure, read the OPF manifest to identify the spine (reading order), then render each chapter as HTML in your browser. Images and stylesheets are resolved relative to each chapter and inlined as Blob URLs.

Question 3

Which EPUB versions are supported?

Accepted Answer

EPUB 2 (uses NCX for TOC) and EPUB 3 (uses NAV XHTML for TOC). We parse both formats and fall back gracefully — if no NAV is found, we use NCX; if neither exists, we build a TOC from chapter titles.

Question 4

Can I change the font?

Accepted Answer

Yes. Font size (sm / md / lg / xl / 2xl), font family (sans / serif / mono), and a dark / light reading mode toggle. Settings are saved to localStorage per book so they persist between sessions.

Question 5

Can I search within the book?

Accepted Answer

Yes. The search bar scans every chapter's text content and returns matching paragraphs with surrounding context. Click a result to jump straight to that chapter.

Question 6

What extra features does this tool have compared to others?

Accepted Answer

10 extras: (1) Drag-drop file. (2) Chapter list sidebar with current-chapter highlight. (3) Font family selection (sans / serif / mono). (4) Dark / light reading mode. (5) Bookmark chapter (localStorage — resume from last chapter on reopen). (6) Search within book text with result jumping. (7) Reading progress percentage (chapters read / total). (8) Copy selected chapter text. (9) File info panel — title, author, chapter count, file size. (10) History of recently opened books (localStorage).

Question 7

Is my book uploaded anywhere?

Accepted Answer

No. The EPUB is parsed entirely in your browser. Chapter content, images, and metadata never leave your device. Only book titles + current chapter indices are saved to localStorage for resume.

Question 8

What about DRM-protected EPUBs?

Accepted Answer

DRM (Adobe ADEPT, Apple FairPlay, etc.) requires a license key — we cannot decrypt those. If your EPUB fails to open, check that it's DRM-free. Most Project Gutenberg, Standard Ebooks, and Humble Bundle books are DRM-free.

EPUB Reader

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