core-js vs Ziggy

Head-to-head usage across the sites we track.

Top sites by authority

core-js · Ziggy · how many of each technology's sites sit in the web's highest authority tiers

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 · Ziggy · share of sites in each country using one or the other

United States 1,295,217

510

India 433,567

228

Brazil 406,300

136

United Kingdom 402,603

167

Germany 384,505

160

France 315,055

139

Italy 302,259

118

Canada 295,823

152

Audience countries from the Chrome UX Report, top markets of either technology.

Real user performance

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.

Sites that switched

Domains that dropped one technology and adopted the other within about a year, data nobody else gives away free.

All core-js sites · All Ziggy sites