Zero-party data is information that users intentionally and proactively share with a brand — such as preferences, interests, purchase intent, or personal context provided through surveys, quizzes, preference centers, or account settings. Unlike first-party data (which is observed through behavioral tracking), zero-party data is voluntarily given by the individual. Because the user is the source and has explicitly provided the information, zero-party data typically has a clear lawful basis under GDPR without requiring cookie consent for its collection. It is increasingly seen as a privacy-first alternative to behavioral profiling as third-party cookie deprecation limits behavioral targeting data.