Which browsers are supported?

Use a current version of Chrome, Safari, Firefox, or Edge — whichever you like. The tools use modern browser features for rendering covers and building PDFs, so an up-to-date browser matters.

Two things to avoid:

• Private / incognito windows. They throw away all local storage when you close them, so your book would vanish. Do real work in a normal window.
• Very old or unusual browsers, or ones with aggressive script-blocking extensions, which can stop the tools from running.

If a tool seems frozen or blank, see The page is frozen or not responding.