Experimenting with the proposed Cross-Origin Storage API in Transformers.js

Different websites can make a browser download the same AI model repeatedly because browser caches separate sites for privacy. The proposed Cross-Origin Storage API would let participating applications reuse an identical file across sites, identifying it by a cryptographic fingerprint of its contents rather than its address. Transformers.js has an experimental integration for this approach.

The June 2026 walkthrough tests the idea through a browser extension; it says no browser implements the API natively at that point. Privacy protections are still being developed because checking which files are cached can reveal browsing activity. The proposal targets duplicate downloads while leaving that privacy problem central to its design.