The Lens

SuperTokens is the open source authentication platform: signup, password reset, social login, multi-factor auth, without Auth0 prices or Firebase lock-in. It handles session management, email verification, passwordless login, and social OAuth out of the box.

Self-hosting is free with all features. The managed cloud has a free tier up to 5,000 monthly active users (MAUs), which covers most startups. Paid tiers kick in at scale.

The catch: the self-hosted version requires running a Java-based core service alongside your app. That's a real dependency: Java runtime, separate process, separate database. The cloud version eliminates this but you're trusting a smaller company with your auth. And the SDK ecosystem, while growing, is narrower than Auth0's. Check that your framework is supported before committing.