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+
8
0
Open Page Rank 8+
52
74
Open Page Rank 7+
204
244
Open Page Rank 6+
435
384
Open Page Rank 5+
761
543
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
5,929
826
United Kingdom
2,191
538
Germany
1,966
722
India
2,032
646
France
1,962
530
Canada
1,813
289
Netherlands
1,488
490
Brazil
1,323
589
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, Sep 2026. Lower is better; green meets Google's "good" threshold. This describes the sites that use each technology, not the technology's own overhead.