Outlook Web App vs RoundCube
Head-to-head usage across the sites we track.
Top sites by authority
Outlook Web App · RoundCube · how many of each technology's sites sit in the web's highest authority tiers
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 · RoundCube · share of sites in each country using one or the other
United States
2,704
790
India
1,547
638
Germany
1,268
721
United Kingdom
1,345
526
France
1,078
491
Brazil
874
581
Canada
1,153
285
Spain
973
447
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Outlook Web App | RoundCube |
|---|---|---|
| LCP | 1.7 s | 1.5 s |
| INP | 75 ms | 75 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.
Sites that switched
Domains that dropped one technology and adopted the other within about a year, data nobody else gives away free.
RoundCube to Outlook Web App
| Domain | When |
|---|---|
| hti.am | Jul 2026 |