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+
401
7
Open Page Rank 7+
1,141
22
Open Page Rank 6+
1,788
24
Open Page Rank 5+
2,572
29
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
25,512
82
Canada
6,167
63
India
4,899
68
United Kingdom
4,567
62
Australia
4,029
48
Germany
3,412
47
France
3,284
48
Spain
3,112
48
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Optimizely | UserZoom |
|---|---|---|
| LCP | 2 s | 2.1 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, 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.
Optimizely to UserZoom
| Domain | When |
|---|---|
| redhat.com | Jan 2026 |