Glassbox vs Site Kit
Head-to-head usage across the sites we track.
Top sites by authority
Glassbox · Site Kit · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
1
38
Open Page Rank 8+
3
649
Open Page Rank 7+
15
2,684
Open Page Rank 6+
36
5,882
Open Page Rank 5+
59
12,397
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Glassbox · Site Kit · share of sites in each country using one or the other
United States
238
191,744
India
153
94,995
Japan
94
73,790
Brazil
82
71,181
United Kingdom
172
64,452
France
115
63,629
Spain
123
63,132
Italy
113
58,351
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Glassbox | Site Kit |
|---|---|---|
| LCP | 2 s | 2.4 s |
| INP | 125 ms | 75 ms |
| CLS | 0 | 0 |
| TTFB | 700 ms | 1300 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.