Outlook Web App vs Zimbra
Head-to-head usage across the sites we track.
Top sites by authority
Outlook Web App · Zimbra · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 8+
11
38
Open Page Rank 7+
29
162
Open Page Rank 6+
50
284
Open Page Rank 5+
68
436
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Outlook Web App · Zimbra · share of sites in each country using one or the other
United States
3,011
960
India
1,731
790
Germany
1,446
533
United Kingdom
1,538
405
France
1,326
591
Brazil
997
903
Italy
1,055
601
Indonesia
860
775
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Outlook Web App | Zimbra |
|---|---|---|
| LCP | 1.7 s | 1.7 s |
| INP | 75 ms | 100 ms |
| CLS | 0 | 0 |
| TTFB | 700 ms | 600 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.