The Web Fonts Working Group has published Incremental Font Transfer as a W3C Candidate Recommendation. This specification defines a method to incrementally transfer a font from server to client. The client loads only the portion(s) of the font that they actually need, significantly reducing data transfer. Multiple incremental additions to the same font are possible, such as a user agent updating a font as a user browses multiple pages. Incremental transfer improves on unicode-range by avoiding damage to layout (kerning, ligatures, etc) rules, meaning it can efficiently support fine grained increments to latin and to complex scripts like Indic or Arabic.
Comments are welcome via GitHub issues by 31 October 2025.