Authress

Seamless Integration of SSO, MFA, passwordless auth and more. Includes SDKs for frontend and backend apps. Free up to 1000 MAUs and five identity providers.

Auhtorization-as-a-service provider platform enabling RBAC, ABAC, and ReBAC for scalable microservices with real-time updates and a no-code policy UI. A 1000 Monthly Active User free tier.

MojoAuth makes it easy to implement Passwordless authentication on your web, mobile, or any application in minutes.

Keycloak Identity and Access Management as a Service. Free up to 100 users and one realm.

Open source user authentication that natively integrates into your app - enabling you to get started quickly while controlling the user and developer experience. Free for up to 5000 MAUs.

Open-source authentication that doesn't suck. The most developer-friendly solution, getting you started in just five minutes. Self-hostable for free, or offers a managed SaaS version with 10k free Monthly Active Users.

Enterprise SSO (SAML, OIDC), SCIM provisioning, and social logins for B2B SaaS. Free tier includes 1 million MAU, 100 organizations, 1 SSO connection, and 1 SCIM connection.

A Sell to companies of any size immediately with a few lines of code, free up to 200 users and 10k Transactional Emails (with a watermark branding: "Powered by PropelAuth").