demo · v138

Shared HTTP cache for pervasive resources

Browse the simulated session. Each site loads a few popular shared scripts. Toggle the policy: pre-138 fully-partitioned cache means each origin re-downloads; 138's "extremely pervasive" carve-out lets specific allow-listed resources cross-origin-cache, restoring the old CDN benefit without re-introducing the privacy leak.

partitioned (pre-138 default) shared for pervasive (138+)

KB downloaded

cache hits

cache misses

resource	via	result

the model

// Pre-138: cache key = (URL, top-level site)
//   → news.example reloads jquery.js even if shop.example just cached it.
// 138+: an allowlist of "extremely pervasive" CDN-hosted resources
//   bypasses the partition: cache key = URL only.
//   The allowlist is browser-curated and excludes anything user-specific.

the model

see also