Incremental Font Transfer

[svgeesus]

こんにちは TAG-さん!

I'm requesting a TAG review of Incremental Font Transfer.

Incremental transfer allows clients to load only the portions of the font they actually need which speeds up font loads and reduces data transfer needed to load the fonts; a font can be loaded over multiple requests where each request incrementally adds additional data.

• Explainer¹: https://github.com/w3c/IFT/blob/main/IFT-Explainer.md
• Specification: https://www.w3.org/TR/2025/WD-IFT-20250220/
• WPT Tests: Not yet
• User research: https://github.com/w3c/IFT/blob/main/IFT-Explainer.md#motivating-use-cases
• Security and Privacy self-review²: Security self-review answers for 9 July 2024 WD of IFT w3c/IFT#194
• GitHub repo: https://github.com/w3c/IFT
• Primary contacts:
  • Garret Rieger (Google Inc.) @garretrieger editor, co-chair
  • Skef Iterum (Adobe Inc.) @skef editor
  • Chris Lilley (W3C)@svgeesus editor
  • Vladimir Levantovsky (W3C Invited Experts) @vlevantovsky co-chair
• Organization/project driving the specification: WebFonts WG
• Multi-stakeholder support³:
  • Chromium comments: (none)
  • Mozilla comments: Incremental Font Transfer mozilla/standards-positions#872
  • WebKit comments: Incremental Font Transfer WebKit/standards-positions#461
  • Several font foundries are interested in testing this approach once it matures and there is code available to create the fonts
• Status/issue trackers for implementations⁴: Not yet

Further details:

• I have reviewed the TAG's Web Platform Design Principles
• Previous early design review, if any: No (but see considered alternatives)
• Relevant time constraints or deadlines:
• The group where the work on this specification is currently being done: WebFonts WG
• The group where standardization of this work is intended to be done (if different from the current group):
• Major unresolved issues with or opposition to this specification:
• This work is being funded by:

You should also know that...

Earlier horizontal review was done on the 9 July Working Draft of IFT; TAG review is requested on today's 20 Feb Working Draft which incorporates feedback from horizontal review and latest developments.

We previously requested review of an earlier approach, which had several problems such as difficulty in deployment, requirement for an active server implementation, fingerprinting risk, and poor performance with CDN caches. The new approach does not suffer from these problems.