What is first-party data and why is it important for tracking?

first-party data privacy cookies customer data tracking

Quick Answer

First-party data is information you collect directly from your customers: emails, purchase history, behavior on your site. Unlike third-party cookies (dying in browsers), first-party data is yours forever, privacy-compliant, and essential for server-side tracking that sends hashed customer identifiers to ad platforms.

Full Answer

First-party data comes from your direct relationship with customers: email addresses, phone numbers, purchase history, site behavior. Third-party cookies track users across sites (surveillance) and are being blocked everywhere. First-party data is protected, privacy-compliant when properly consented, and the foundation for effective server-side tracking. When you send hashed emails via Facebook CAPI or Google Enhanced Conversions, you are using first-party data for attribution.