Auth0 is an authentication and authorization platform from Okta, Inc. Authentication checks who a user is; authorization decides what that user may access. Auth0 is a drop-in service: an application sends its users to Auth0 to sign up and log in, instead of building its own login and user management.
Users log in with a username, email or phone number and a password, with social accounts such as Facebook or X, or without a password through one-time codes sent by email or SMS. Universal Login is a login page hosted by Auth0. The platform adds multi-factor authentication (MFA), single sign-on (SSO) across several apps, enterprise login through SAML or a company directory, alerts about breached passwords, and blocking of suspicious IP addresses. It protects APIs with OAuth 2.0, supports role-based and fine-grained authorization, and offers identity tools for AI agents, such as Token Vault and an MCP server. SDKs and quickstarts cover more than 30 languages and frameworks.
Auth0 is a hosted service. The Free plan covers up to 25,000 monthly active users; paid plans are monthly subscriptions priced by the number of monthly active users.