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+
208
0
Open Page Rank 8+
3,591
15
Open Page Rank 7+
17,002
35
Open Page Rank 6+
36,960
43
Open Page Rank 5+
72,129
76
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
1,141,651
309
India
531,962
120
Brazil
414,021
102
United Kingdom
386,042
164
Indonesia
294,061
140
Germany
289,537
319
Canada
280,974
92
Italy
273,070
342
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, 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.
K2 to HTTP/3
| Domain | When |
|---|---|
| fairclothreynolds.com.au | Jul 2026 |
| aliojonava.lt | Jun 2026 |
| clinicapodologicatecnopeu.com | Mar 2026 |