HTTP/3 vs SPDY
Head-to-head usage across the sites we track.
Top sites by authority
HTTP/3 · SPDY · 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
0
Open Page Rank 7+
17,002
1
Open Page Rank 6+
36,960
1
Open Page Rank 5+
72,129
4
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 · SPDY · share of sites in each country using one or the other
United States
1,141,651
23
India
531,962
71
Brazil
414,021
9
United Kingdom
386,042
10
Indonesia
294,061
8
Germany
289,537
9
Canada
280,974
8
Italy
273,070
5
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | HTTP/3 | SPDY |
|---|---|---|
| LCP | 1.9 s | 2.1 s |
| INP | 75 ms | 100 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.