core-js vs Immutable.js
Head-to-head usage across the sites we track.
Top sites by authority
core-js · Immutable.js · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
243
0
Open Page Rank 8+
5,081
8
Open Page Rank 7+
26,045
18
Open Page Rank 6+
56,582
27
Open Page Rank 5+
107,942
38
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
core-js · Immutable.js · share of sites in each country using one or the other
United States
1,320,418
1,058
India
439,882
155
Brazil
411,231
111
United Kingdom
404,005
181
Germany
391,462
135
France
311,727
130
Canada
298,167
566
Italy
291,018
110
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | core-js | Immutable.js |
|---|---|---|
| LCP | 2 s | 1.6 s |
| INP | 75 ms | 75 ms |
| CLS | 0 | 0 |
| TTFB | 800 ms | 600 ms |
Median site's p75 values from the Chrome UX Report, Aug 2026. Lower is better; green meets Google's "good" threshold. This describes the sites that use each technology, not the technology's own overhead.
Sites that switched
Domains that dropped one technology and adopted the other within about a year, data nobody else gives away free.
Immutable.js to core-js
| Domain | When |
|---|---|
| villagesquireestates.com | Jun 2026 |
| natures-mark.com | Nov 2025 |