The best APIs for secure user authentication

In 2024, stolen credentials accounted for 22% of data breaches, escalating to 88% in basic web application attacks, with an average breach cost of $4.67 million. This highlights the inadequacy of authentication systems that prioritize developer convenience over security. The document evaluates six authentication APIs—Clerk, Auth0, Firebase Authentication, Supabase Auth, WorkOS, and AWS Cognito—through a security-first perspective, emphasizing zero-trust principles, token architecture, and compliance certifications. It explores OAuth 2.0 and OpenID Connect (OIDC) frameworks, emphasizing the importance of per-request verification and short-lived tokens. The text also discusses the rise of passkeys as a replacement for passwords, noting their phishing-resistant properties. It provides detailed comparisons of the APIs based on criteria like token management, session validation, and developer experience, while also considering pricing models such as Monthly Active Users (MAU) and Monthly Retained Users (MRU). The document concludes by suggesting that the choice of an auth API should align with a team's specific security needs, technology stack, and scale, with considerations for operational factors like migration and data portability.