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+
51
75
Open Page Rank 7+
205
237
Open Page Rank 6+
433
380
Open Page Rank 5+
754
540
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
5,830
790
Germany
1,938
721
United Kingdom
2,125
526
India
1,985
638
France
1,914
491
Canada
1,752
285
Netherlands
1,445
450
Brazil
1,300
581
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, 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.