The data you see on Leadfeeder is mostly from your Google Analytics. Google Analytics uses a global database to convert IP addresses into Network Reports. Leadfeeder fetches those Network Reports and we also enrich this data with our own information.
Leadfeeder Contacts is part of our Service where we provide business-to-business contact details related to the website leads. The data is gathered from publicly accessible sources by our data partners FullContact Inc. and Hunter Web Services Inc as well as Crunchbase.