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+
3,600
14
Open Page Rank 7+
17,128
31
Open Page Rank 6+
37,410
41
Open Page Rank 5+
72,694
73
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
1,137,483
311
India
533,896
120
Brazil
409,200
100
United Kingdom
387,999
160
Indonesia
291,484
126
Germany
286,932
318
Italy
284,574
331
Canada
281,458
82
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 | 700 ms | 900 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.
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 |
|---|---|
| baoholaodongtot.com | Oct 2026 |
| fairclothreynolds.com.au | Jul 2026 |
| aliojonava.lt | Jun 2026 |
| clinicapodologicatecnopeu.com | Mar 2026 |