W3C invites implementations of HTML ruby markup extensions**

The World Wide Web Consortium has published HTML Ruby Markup Extensions as a Candidate Recommendation Snapshot, inviting implementation experience for an update to how ruby annotations are marked up in HTML.

Ruby annotations are short pieces of text displayed alongside base text. They are commonly used in Japanese, Chinese, and other East Asian writing systems to show pronunciation or provide brief explanations.

The specification revises and extends the existing HTML model for ruby markup. W3C says the current HTML model is useful for simple cases but does not fully cover more complex ruby use cases and is not always interoperably implemented across browsers.

The draft defines how HTML elements such as ruby, rb, rt, rtc, and rp should be used to connect base text with annotations. It also addresses segmentation and pairing, including cases where one annotation applies to multiple characters or where multiple annotation levels are used.

The specification is designed to remain backward compatible with ruby content already supported by existing user agents. It was developed under an agreement between W3C and WHATWG to reduce differences between the extension specification and the HTML Standard over time.

The document will remain at Candidate Recommendation stage at least until 3 July 2026 to allow for review and implementation feedback.