| Product | Logto |
| Website | logto.io |
| Category | Authentication / Identity |
| License | MPL 2.0 (open source) |
| Pricing | Free (50K MAU), Pro $16/mo, enterprise custom |
What Is Logto?
Logto is an open-source authentication and authorization platform. It handles user sign-up, sign-in, social login, passwordless authentication, multi-factor auth, RBAC, and multi-tenancy. Think Auth0 or Clerk, but open-source and self-hostable.
Authentication is infrastructure that every application needs but nobody wants to build. The security stakes are high, the edge cases are endless, and the standards (OAuth 2.0, OIDC, SAML) are complex. Logto provides this infrastructure as a service or as a self-hosted deployment.
Key Features
Sign-In Experience Builder
A visual builder for the sign-in page: choose providers (Google, GitHub, Apple, email, phone), customize branding, configure MFA, and preview the result. Deploy a polished, secure sign-in flow without writing UI code.
Multi-Tenancy for SaaS
Built-in organization support for B2B SaaS: create organizations, invite members, assign roles per organization. Each customer gets their own organization with isolated permissions. This is the feature that separates SaaS-ready auth platforms from basic authentication.
Machine-to-Machine Auth
Issue and manage API keys and machine-to-machine tokens. For SaaS products that expose APIs, Logto handles the authentication layer for both human users and API consumers.
Self-Hosted
Run Logto on your own infrastructure with Docker. Full control over data, customization, and deployment. The self-hosted version includes all features, with no artificial limitations compared to the cloud offering.
Who Is This For?
- SaaS builders who need multi-tenant auth
- Teams looking for an Auth0 or Clerk alternative
- Companies that need self-hosted authentication
- Developers who want open-source auth infrastructure
Pros
- Open source (MPL 2.0)
- Multi-tenancy for B2B SaaS
- Visual sign-in experience builder
- Machine-to-machine auth
- Self-hosted with no feature limits
- Generous free tier (50K MAU)
Cons
- Smaller ecosystem than Auth0
- Self-hosting requires maintenance
- Documentation gaps in advanced features
- Fewer social login providers than Clerk
- Younger project (rapid iteration)
Verdict
Logto is the best open-source authentication platform for SaaS products. The multi-tenancy support, sign-in builder, and machine-to-machine auth cover the full authentication needs of a B2B SaaS application. The MPL 2.0 license and self-hosted option provide the flexibility that Auth0’s pricing and vendor lock-in don’t.
For consumer applications with simple authentication needs, Clerk provides a more polished developer experience. For enterprise SAML and compliance requirements at scale, Auth0 has a deeper feature set. Logto’s sweet spot is SaaS builders who need multi-tenant auth they can self-host and customize.