co.jp vs Proton Mail

Proton Mail is used by more websites in our catalog: 205 use co.jp and 1,505 use Proton Mail.

co.jp sites have the higher median Ahrefs Domain Rating (co.jp: 60, Proton Mail: 30).

Between 2026-06 and 2026-07, co.jp went from 0.03% to 0.02% of all tracked sites, while Proton Mail went from 0.21% to 0.17%. co.jp is gaining ground faster in our index.

No. A site runs a single email host, so co.jp and Proton Mail are mutually exclusive.

Adoption is counted from Site Stats Database's own crawl; Domain Rating comes from Ahrefs and traffic from DataForSEO. Figures reflect the sites we track and refresh at least monthly.