I notice that subdomain discovery results can vary significantly between providers. Why is that?

Subdomain discovery results heavily depend on data collection, aggregation, and cleaning methods. Certain methods or the inability to apply them may lead to a lot of noise, notably due to automatically generated attempts of random, pseudo-random, or possibly-known (with variations) host names that get recorded in pDNS databases. These automated attempts tend to over-inflate results, distract investigations, and distort analyses.

Results from our Subdomains Lookup API are cleaned to reduce noise and improve data accuracy.