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+
13
38
Open Page Rank 7+
32
156
Open Page Rank 6+
49
274
Open Page Rank 5+
67
420
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
2,704
840
India
1,547
718
Germany
1,268
440
United Kingdom
1,345
356
Brazil
874
817
France
1,078
514
Italy
921
515
Canada
1,153
270
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, 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.