v138 · network / connectivity
Pervasive Resource Tester
Fetch a set of well-known CDN resources twice and measure how timing changes between first and second load, then simulate cross-site navigation savings that Chrome 138's single-keyed pervasive cache unlocks. Use the criteria inspector to understand exactly why a URL is or is not eligible.
Fetch timing probe
—
resources tested
—
fast on 2nd fetch
—
KB potentially shared
Results — round 1 vs round 2
Click "Run fetch probe" to start.
Byte savings vs re-download
Cross-site navigation simulator
Simulates loading the same pervasive resource (e.g. a popular framework) across 5 different origins. Without the pervasive cache each origin's partition re-downloads it; with Chrome 138 the single-keyed entry is reused.
Eligibility criteria inspector
Preset URLs
Criteria checklist
| Criterion | Result |
|---|---|
| Select a URL on the left | |
How Chrome 138 decides: Chrome maintains a hard-coded allowlist of a few
hundred extremely-pervasive resources (popular CDN-served scripts, stylesheets, and
compression dictionaries used across a large fraction of the web). Only resources on this
allowlist and loaded with a matching
integrity attribute bypass cache partitioning
and land in a single shared entry. The privacy bar is that only static, immutable, version-locked
resources with a known hash are eligible — dynamic or personalized content never qualifies.