Auth0

What is Auth0?

Auth0, now part of Okta, is an identity platform built for the harder end of authentication: single sign-on, SAML/OIDC federation, and managing auth across many separate customer organizations, not just a login form for your own app. It's the option teams reach for when "add login" turns into "support enterprise customers' existing identity providers."

Key features

• Universal Login handles the actual auth UI, with customization for branding
• SSO and SAML/OIDC federation for enterprise customers who need to connect their own identity provider
• Organizations feature for B2B apps managing multiple separate customer tenants
• Extensive rules/actions system for customizing the auth flow (custom claims, MFA logic, etc.)
• Broad ecosystem of SDKs and integrations across web, mobile, and backend stacks

Who it's for

Makes the most sense once you're selling to businesses that expect SSO and have their own identity requirements. For a straightforward consumer app's login flow, it's more platform than you need, Clerk or Better Auth are lighter starting points.

Pricing

Free tier for low active-user counts, with paid tiers scaling by monthly active users and gated features like advanced SSO and organizations. Check the site for current limits.