supertokens
Open source alternative to Auth0 / Firebase Auth / AWS Cognito
logto-io
🧑🚀 Authentication and authorization infrastructure for SaaS and AI apps, built on OIDC and OAuth 2.1 with multi-tenancy, SSO, and RBAC.
hexclave
Open-source Auth0/Clerk alternative
stack-auth
Open-source Auth0/Clerk alternative