HTTP/3 vs K2
Head-to-head usage across the sites we track.
Top sites by authority
HTTP/3 · K2 · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
217
0
Open Page Rank 8+
3,633
16
Open Page Rank 7+
17,286
41
Open Page Rank 6+
37,596
50
Open Page Rank 5+
73,412
87
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
HTTP/3 · K2 · share of sites in each country using one or the other
United States
1,284,004
373
India
592,975
138
United Kingdom
436,501
184
Brazil
418,679
115
Indonesia
328,375
181
Canada
321,328
106
Germany
316,957
396
Italy
305,727
395
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | HTTP/3 | K2 |
|---|---|---|
| LCP | 1.9 s | 1.9 s |
| INP | 75 ms | 75 ms |
| CLS | 0 | 0 |
| TTFB | 800 ms | 900 ms |
Median site's p75 values from the Chrome UX Report, Jun 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.
K2 to HTTP/3
| Domain | When |
|---|---|
| clinicapodologicatecnopeu.com | Mar 2026 |