fastmail.com
Email providerAbout this data
How it is collected. Market Insights is built entirely from publicly observable data: domains seen across the internet and the DNS servers that answer for them. We attribute each domain to a provider based on the DNS infrastructure serving it, and aggregate those signals into the figures shown here.
Why it can differ from reality. This is an automated estimate, not an official registry. A provider’s real footprint can be higher or lower than shown, especially when it does not use its own DNS servers to host customer domains (for example, when those domains sit on a registrar’s, reseller’s or third-party cloud DNS). Coverage, timing and DNS configuration all affect what we can see.
The tool is neutral and provided “as is”. The same automated method is applied to every provider, with no manual ranking, no favoritism and no paid placement. These figures are published for informational purposes only, without any warranty of accuracy or completeness, and we accept no liability for any discrepancies or for decisions made based on this data.
Think a company is under-counted? We’d genuinely like to fix it. Send us your domain list or report your DNS servers, and we’ll review the attribution.