Open the public proof: [/data/coverage](/data/coverage), country pages (United States ~225.4 million profiles / ~120.3 million personal emails; United Kingdom ~40.6 million / ~17.9 million), and [/data/methodology](/data/methodology). Also compare [Mawsool vs Hunter.io](/compare/mawsool-vs-hunter-io) and [Mawsool vs Kaspr](/compare/mawsool-vs-kaspr).
Vendor size for ContactOut: 350M+ professionals across ~40M companies (ContactOut claims). Source class: ContactOut / industry pages. Treat every vendor headline as a claim until you sample your ICP. Definitions of contact, profile, and email are not identical across vendors — that is why Mawsool publishes both profile and personal-email totals with a date.