Logto

Every team shipping a SaaS product ends up implementing OIDC and OAuth 2.1 again, and Logto exists to stop that. It is open source auth infrastructure for SaaS and AI apps, where multi-tenancy, enterprise single sign on and role-based access control arrive ready to use rather than as workarounds layered onto a simpler product.

Sign-in flows come pre-built with customizable UIs, and SDKs cover more than thirty frameworks including React, Next.js, Angular, Vue, Flutter, Go and Python. The same setup serves single page apps, web apps, mobile apps, APIs, machine to machine calls and CLI tools, while connectors bring in outside identity providers such as Google, Facebook, Azure AD and Okta.

Getting a working instance takes one of three routes.

• Logto Cloud: a fully managed instance with zero setup, the fastest way to try the product.
• GitPod: launches the open source build in a browser in seconds.
• Local development: Docker Compose brings the stack up, or npm init runs it on Node.js against your own PostgreSQL.

Organization RBAC, member invitations and just-in-time provisioning cover the multi-tenant side, with SAML alongside the OAuth family for enterprise customers who need it.

Beyond the standard protocols, Logto documents support for Model Context Protocol and agent-based architectures, which matters when the thing signing in is not always a person.