Fastmail vs IONOS

IONOS is used by more websites in our catalog: 1,580 use Fastmail and 7,789 use IONOS.

Fastmail sites have the higher median Ahrefs Domain Rating (Fastmail: 38, IONOS: 20).

Between 2026-06 and 2026-07, Fastmail went from 0.22% to 0.18% of all tracked sites, while IONOS went from 0.97% to 0.88%. Fastmail is gaining ground faster in our index.

No. A site runs a single email host, so Fastmail and IONOS 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.