Optimizely vs UserZoom
Head-to-head usage across the sites we track.
Top sites by authority
Optimizely · UserZoom · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
31
2
Open Page Rank 8+
400
7
Open Page Rank 7+
1,147
22
Open Page Rank 6+
1,808
25
Open Page Rank 5+
2,607
30
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Optimizely · UserZoom · share of sites in each country using one or the other
United States
28,637
95
Canada
7,019
71
India
5,573
72
United Kingdom
5,243
69
Australia
4,573
52
France
4,064
59
Germany
3,936
59
Spain
3,659
59
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Optimizely | UserZoom |
|---|---|---|
| LCP | 2 s | 2.4 s |
| INP | 100 ms | 100 ms |
| CLS | 0.05 | 0 |
| TTFB | 800 ms | 700 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.
Optimizely to UserZoom
| Domain | When |
|---|---|
| redhat.com | Jan 2026 |