Sigil is a free, open source multi-platform EPUB ebook editor that runs on Linux, macOS, and Windows.
Sigil addresses the need for a dedicated tool to create and modify EPUB ebooks, which are the standard format for digital publishing. The editor works with both EPUB 2 and EPUB 3 specifications. It provides a graphical interface built on Qt6 and QtWebEngine, allowing users to edit ebook content directly rather than working with raw XML files or command-line tools.
Sigil suits authors, publishers, and ebook enthusiasts who need to create, modify, or validate EPUB files without relying on proprietary software. It works well for anyone producing digital books for distribution or personal use. The tool is particularly valuable for those who want full control over ebook structure and formatting while maintaining open source transparency. The project maintains a plugin system that extends functionality, with a community-maintained plugin index available through its support forums.
The project maintains clear boundaries around its issue tracker, directing feature requests and questions to its dedicated forum rather than GitHub issues, which keeps code discussion focused on actual bugs and implementation problems. Development documentation is comprehensive, with separate build guides for different operating systems and dependency configurations, reflecting attention to supporting users across varied Linux distributions, macOS versions, and Windows platforms. The codebase has recently upgraded to require Qt6.4 as a minimum, indicating active modernization of its dependencies while maintaining documentation for building with older Qt5 for systems that cannot upgrade.
