Building Production Auth: The PostgreSQL Database Architecture Behind Secure Authentication

A production authentication system's reliability and performance depend critically on thoughtful database design. This detailed breakdown reveals how eight carefully structured PostgreSQL tables, combined with strategic indexing and extension usage, create a robust foundation for multi-method authentication—from OAuth and magic links to passkeys and email verification. Understanding these foundational decisions, such as preferring bigserial over UUID for primary keys and leveraging citext for case-insensitive email matching, provides practical lessons applicable across any data-driven system.