Proton Mail vs RoundCube
Head-to-head usage across the sites we track.
Top sites by authority
Proton Mail · RoundCube · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
7
0
Open Page Rank 8+
47
73
Open Page Rank 7+
198
243
Open Page Rank 6+
418
378
Open Page Rank 5+
737
544
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Proton Mail · RoundCube · share of sites in each country using one or the other
United States
6,185
917
United Kingdom
2,300
583
Germany
2,033
827
India
2,067
690
France
2,126
597
Canada
1,910
313
Netherlands
1,566
525
Brazil
1,346
614
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Proton Mail | 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, 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.