Auth0

Auth0 (now part of Okta as the Okta Customer Identity Cloud) is a flexible, drop-in authentication and authorization platform for web, mobile, IoT, and legacy applications. It handles the full identity lifecycle — including social logins, passwordless authentication, multi-factor authentication (MFA), single sign-on (SSO), and enterprise federation — so developers can focus on building features rather than identity infrastructure. Auth0 supports B2B, B2C, and B2E use cases and offers extensive SDKs, APIs, and compliance tooling for standards such as SOC 2, ISO 27001, GDPR, and HIPAA.