Sigil is a multi-platform WYSIWYG ebook editor. It is designed to edit books in ePub format.
Features
Free and open source software under GPLv3
Multi-platform: runs on Windows, Linux and Mac
Full Unicode support: everything you see in Sigil is in UTF-16
Full EPUB spec support
WYSIWYG editing
Multiple Views: Book View, Code View and Split View
Metadata editor with full support for all possible metadata entries (more than 200) with full descriptions for each
Table Of Contents editor
Multi-level TOC support
Book View fully supports the display of any XHTML document possible under the OPS spec
SVG support
Basic XPGT support
Advanced automatic conversion of all imported documents to Unicode
Currently imports TXT, HTML and EPUB files; more will be added with time
Currently exports EPUB and SGF (Sigil native format); more will be added with time
Embedded HTML Tidy; all imported documents are thoroughly cleaned; changing views cleans the document so no matter how much you screw up your code, it will fix it (usually)
An actually usable user interface
Native C++ application
What’s new in version 1.9.30
Updated on Mar 17 2023
Bug Fixes
fix Checkpointing to work with dulwich version 0.20.46+
fix css value parsing when !important is used
EmbeddedPython fixes to work with Python 3.11 and later (thank you sharkcz)
leave cursor position unchanged if nothing found when search groups of files
make all Numeric items in Reports align right
add support for thousands separator to Reports
allow blank dc:language values to prevent crashing (as Sigil-1.9.10 did)
allow unknown language codes to pass through MetaEditor
MetaEditor under epub2, allow custom opf scheme values
prevent duplicate spaces when reformatting CSS in import, charset and namespace
better prevent random OPF attribute order changes to simplify Checkpoint diffs
fixed file menu Print Preview for xhtml and image tabs
prevent plugins from crashing Sigil by deleting last xhtml file in epub
fix issue where images/css could not be properly added in an epub3 with no css files
New Features
allow user to edit Checkpoint descriptions for clarity via Checkpoint menu
add ability to show the Checkpoint Change Log via Checkpoint menu
update to Hunspell 1.7.2 (released in December 2022) for spellchecking
update to latest zlib-1.2.13 for latest security fixes
move completely away from ever using OS system tmp folder for storing Sigil wip files. Instead create a new "workspace" folder inside Sigil Preferences folder
added ability to Print Preview and Print contents of Sigil's Preview window
Will sigil ever be compatible with the M1 processor?? I've tried multiple times this year (Nov 12, 2021 today) and it never works. Have a 2020 MacBook Air.
Just a note: This hasn't been a WYSIWYG editor in a while. The dev removed that portion of the app and split it off into a separate app called PageEdit (also open source).
I have used this app only once when Amazon was refusing my book in Calibre's mobi format and it saved my life. :-)
I opened with Sigil the epub generated by Calibre and generated the TOC (Tools/Toc/Generate at that time) then I opened the edited epub in Kindle Previewer or kindlegen and converted to mobi.
So 5 stars for this invaluable tool!
8.01 is out at http://sigildev.blogspot.it
A really nice and great application to create or edit epub.
My only complaints with these last versions (8.0 and 8.01) is that you can not paste text in the Replace field using key shortcut anymore.
It is not a tragedy, but it's not so comfortable activate the control-click menu every time you want paste the replace string in Search and Replace…
So before to upgrade take also a backup copy of previous version if it works for you.
Great software, unfortunately no longer under active development. See: http://sigildev.blogspot.com
I am still using it in Mavericks. I use Calibre also, which is constantly improving as an ebook editor.
CANT RUN IT ON MAC 10.6.8 and someone ?? can't be bothered to put the new version of SIGIL on the MACUPDATE page
BOTH versions of SIGIL fail to load with MAC 10.6.8 ( Sigil 6.2 and 7.1 )
Actually, 0.6.2 is out, but hold off. More and more people are reporting that it crashes on start up in OSX. Someone really needs to catch up on this listing at MacUpdate.