Auth0

Auth0 is an identity-as-a-service platform that provides authentication, authorization, and user management for web, mobile, and API applications. Founded in 2013 by Eugenio Pace and Matias Woloski in Buenos Aires, Auth0 was acquired by Okta in 2021 for $6.5 billion, making it one of the largest identity platform acquisitions in history. Auth0 serves over 16,000 customers including Mozilla, Mazda, Sharp, and Siemens. The platform's core value proposition is letting developers implement enterprise-grade authentication — social logins, multi-factor authentication, single sign-on, and passwordless flows — without building or maintaining identity infrastructure from scratch.

Universal Login and Authentication Flows

Auth0's Universal Login provides a centralized, customizable login page that handles the complexity of authentication flows. It supports username/password, social connections (Google, GitHub, Facebook, Apple — over 30 providers), enterprise connections (SAML, LDAP, Active Directory, Azure AD), and passwordless authentication via email magic links or SMS codes. Universal Login handles security best practices automatically: brute-force protection, breached password detection, bot detection, and adaptive MFA. The New Universal Login experience allows extensive customization through a visual editor or custom HTML/CSS/JS, letting teams match their brand without sacrificing security.

Actions and Extensibility

Auth0 Actions is a serverless extensibility framework that lets developers run custom Node.js code at specific points in the authentication pipeline — post-login, pre-registration, post-password-change, and during machine-to-machine token exchange. Use cases include enriching user tokens with custom claims from your database, enforcing conditional access policies (block logins from specific countries, require MFA for admin roles), syncing user data to external systems on registration, and implementing progressive profiling that collects additional user information over time. Actions replaced the older Rules and Hooks systems with a more structured, debuggable approach that includes a built-in editor, version history, and secret management.

Organizations and B2B Identity

Auth0 Organizations is designed for B2B SaaS applications that need multi-tenant identity management. Each organization (your customer) can have its own branding, login experience, connection configuration (enterprise SSO via their own SAML/OIDC provider), member management, and MFA policies. This is critical for B2B SaaS companies whose enterprise customers require connecting Auth0 to their corporate identity provider — a common requirement for selling to companies with over 500 employees. Without Organizations, implementing multi-tenant SSO requires complex custom code; Auth0 handles the tenant isolation and connection routing automatically.

Security and Compliance

Auth0 provides enterprise security features including Attack Protection (brute-force, bot detection, breached password detection), adaptive MFA that adjusts authentication strength based on risk signals, and detailed audit logs for compliance. The platform is SOC 2 Type II certified, HIPAA-eligible, and GDPR-compliant, with data residency options in the US, EU, and Australia. Security Center provides a centralized view of authentication-related threats and anomalies across all your applications.

Pricing Considerations

Auth0 offers a free plan with up to 7,500 monthly active users (MAU) and 2 social connections. The Essentials plan starts at $35/month for 500 MAU with additional MAU priced in tiers. The Professional plan at $240/month adds custom domains, MFA, and up to 20 social connections. Enterprise pricing is custom and required for Organizations, advanced security features, and SLA guarantees. The MAU-based pricing can become expensive for consumer-facing applications with large user bases, and the jump from free to Professional is steep for startups that need features like custom domains or MFA.