- Free and open source software under GPLv3
- Multi-platform: runs on Windows, Linux and Mac
- Full UTF-16 support
- Full EPUB 2 spec support
- Multiple Views: Book View, Code View and Preview View
- WYSIWYG editing in Book View
- Complete control over directly editing EPUB syntax in Code View
- Table of Contents generator with multi-level heading support
- Metadata editor with full support for all possible metadata entries (more than 200) with full descriptions for each
- User interface translated into many languages
- Spell checking with default and user configurable dictionaries
- Full Regular Expression (PCRE) support for Find & Replace
- Supports import of EPUB and HTML files, images, and style sheets,
- Documents can be validated for EPUB compliance with the integrated FlightCrew EPUB validator
- Embedded HTML Tidy: all imported files have their formatting corrected, and your editing can be optionally cleaned
- Set minimum OS X version to 10.9.0 in Info.plist so users trying to run on older versions of OS X will receive an error dialog instead of a crash dialog.
- Set minimum Windows version to Vista in Installer so installation will error when trying to install on XP (which is not supported and Sigil binary packages won't run on).
- Fix issue #21: Use Hunspell WORDCHARS to help in tokenization of words.
- Pull request #19: Moving plugin description to ToolTips.
- Pull request #20: Preserve current file name for future save as actions if appropriate.
- Fix bug where save after using input plugin would fail.
Software that can be used as an alternative to Sigil: