core-js vs Karma
Head-to-head usage across the sites we track.
Top sites by authority
core-js · Karma · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
242
1
Open Page Rank 8+
5,039
1
Open Page Rank 7+
25,753
1
Open Page Rank 6+
55,778
1
Open Page Rank 5+
106,331
3
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 · Karma · share of sites in each country using one or the other
United States
1,295,217
26
India
433,567
24
Brazil
406,300
23
United Kingdom
402,603
25
Germany
384,505
24
France
315,055
23
Italy
302,259
21
Canada
295,823
26
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | core-js | Karma |
|---|---|---|
| LCP | 2 s | 1.4 s |
| INP | 75 ms | 100 ms |
| CLS | 0 | 0 |
| TTFB | 800 ms | 600 ms |
Median site's p75 values from the Chrome UX Report, Sep 2026. Lower is better; green meets Google's "good" threshold. This describes the sites that use each technology, not the technology's own overhead.