Is RTL supported?

GitBook supports Right-to-Left languages. The language direction should be detected automatically. If not, you can try to specify a language in your book.json (ex: ar), or you can force GitBook to use rtl in your book.json:

"direction": "rtl",
"language": "ar"

Note that in the Editor, RTL writing is not yet supported. But it will correctly display in the final output, after publishing.