BookYourData fills the missing fields in your contact file through Data Appending, a done-for-you service that matches each missing field against 1,000+ live sources at the time of your order. The sources are checked when you place the order, so the appended data reflects what those sources hold at that moment.
The matching process works field by field. Every email added through Data Appending passes real-time email verification before it reaches you, so the addresses in your updated file have been checked for deliverability.
Data Appending works on contact files you already own.
To read more about the service, visit bookyourdata.com/data-appending. Additional help articles are available at intercom.help/bookyourdata/en/.