What is FB2?

FB2 (FictionBook 2.0) is an open XML-based eBook format developed in Russia, emphasizing semantic structure over presentation. Unlike EPUB which focuses on styling, FB2 uses XML tags to define content meaning (author, title, chapter, poem, epigraph, etc.). Readers can apply their own stylesheets for custom appearance. FB2 files are plain text XML (often zipped to .fb2.zip or .fbz), making them easy to create, edit, and process programmatically.

FB2 is the dominant eBook format in Russia and former Soviet countries, used by major digital libraries like Lib.ru, Flibusta, and numerous reading apps (FBReader, CoolReader, Moon+ Reader). Popular for fiction, especially classic literature and fan translations. FB2's rich metadata and semantic structure make it ideal for cataloging and searching large book collections. Can be converted to EPUB or MOBI for Kindle. Supported by Calibre for library management.

Did you know? FB2 is XML-based, so you can edit eBooks in any text editor!

History

FB2 was created by Russian software developer Dmitry Gribov as an open alternative to proprietary eBook formats, quickly becoming the standard in Russian-speaking countries.

Key Milestones

  • 2004: FB2 format specification published
  • 2005: FBReader adoption begins
  • 2008: Russian library dominance
  • 2011: FB2.1 specification
  • 2016: FB3 development starts
  • Present: Standard in Eastern Europe

Key Features

Core Capabilities

  • Semantic XML: Meaning-based markup
  • Rich Metadata: Author, genre, translator info
  • Open Format: No DRM restrictions
  • Plain Text: Human-readable XML
  • Embedded Images: Base64 encoding
  • Styling Freedom: Reader-customizable

Common Use Cases

Russian eBooks

CIS digital libraries

Fiction

Novels and literature

Translations

Fan translations

Cataloging

Book collection management

Advantages

  • Open and free format
  • Semantic structure (content over style)
  • Excellent metadata support
  • Plain text XML (easy to edit)
  • No DRM restrictions
  • Widespread in Russia/CIS
  • Small file sizes

Disadvantages

  • Limited Western adoption
  • No complex layouts (like textbooks)
  • Base64 images increase size
  • Less Kindle compatibility
  • Fewer editing tools than EPUB
  • Not ideal for illustrated books

Technical Information

Format Specifications

Specification Details
File Extension .fb2, .fb2.zip, .fbz
MIME Type text/xml
Base Format XML (plain text)
Structure Semantic markup
Images Base64-encoded embedded
Status Active (popular in Russia)

Common Tools

  • Readers: FBReader, CoolReader, Moon+ Reader, AlReader
  • Management: Calibre (full support)
  • Creation: Fiction Book Designer, any XML editor
  • Conversion: Calibre, fb2converter, online tools