What is a .FB3 file?
FB3 is the ZIP-based successor to the FictionBook e-book format.
- Did you know
- FB3 modernised FictionBook by switching to a ZIP-and-XML structure.
- FB3 was developed by the Russian retailer LitRes as a layout-capable successor to FictionBook 2.
- Its packaging follows the ECMA-376 Open Packaging conventions, and unlike FB2 it no longer embeds images as Base64 text blocks.
- What Analyser reads
- Open documents, ebooks and publishing files beyond Office: comic books (CBZ/CBT with ComicInfo + first-page preview; CBR/CB7 identified), Microsoft XPS, FictionBook FB3, iBooks, Scrivener, Visio VSDX, R Markdown/Quarto, RTFD, WARC/MAFF web archives, TeX DVI, legacy Hangul HWP, and WordPerfect/QuarkXPress/PageMaker identification.
- Depth of analysis
- .FB3 is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .FB3 file
- Drag a .FB3 file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.