First-party data is simply the company’s own data about their customers. It is information the company itself has gathered about their customer from their web site interactions, their purchase history, subscription data, and cross-platform data from mobile web or apps. Since it is collected by the company, it is generally thought of as the most valuable because of its quality. In the case of first-party data, the customer is known to the marketer. First-party data is the highest quality and most reliable of all data types. It is first-hand insight and information about customers.