Open Source Firebase Authentication Alternatives

Authentication in the TypeScript ecosystem is a half solved problem, in the view of Better Auth's author, and this library is the answer he built: a framework for authentication and authorization that ties itself to no particular web framework. The alternatives handle a basic login and then ask for a lot of extra code for anything past it, and the usual fallback is to hand the whole problem to a third party service.

The answer here is a plugin ecosystem. The core ships a set of features out of the box, and anything more advanced arrives as a plugin, so a feature that would otherwise be a project of its own becomes a small amount of code.

The README names the ground this is meant to cover.

• Framework agnostic: no assumption about which TypeScript framework the application is built on.
• Authorization included: access rules treated as part of the same problem, not a separate library.
• Two factor authentication: available through the plugin system rather than hand rolled.
• Multi tenant support: tenancy handled the same way, again as a plugin.

The project is free and open source under the MIT license, with contributions, feature suggestions and issue reports all invited. Security vulnerabilities go through GitHub Security Advisories, where the maintainers say reports are addressed promptly and reporters credited.

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.

SuperTokens adds secure login and session management to an application without handing your user table to somebody else. It is an open-core alternative to proprietary login providers, free with no limit on the number of users, and deployed on premises so the data sits in a database you control.

The design splits into three parts. A frontend SDK renders login widgets and manages session tokens, a backend SDK exposes the sign-up, sign-in, sign-out and refresh APIs your frontend calls, and the SuperTokens Core is an HTTP service holding the auth logic and database operations the backend SDK talks to. The core is Java, shipped with its own JDK in the binary and Docker image, so running it resembles running any other HTTP microservice.

Features are deliberately decoupled, so you can adopt only the pieces you need.

• Login methods: passwordless, social, email password and phone password sign-in.
• Session management: token handling that also integrates with other login providers, including Auth0.
• Multi-factor authentication: a second factor layered onto any of the login methods.
• Multi-tenancy: organization support with enterprise SSO for customers who bring their own identity provider.
• Authorization: user roles alongside authentication between microservices.

Session verification happens inside the backend SDK without contacting the Java core, so one core instance serves tens of thousands of users. SDKs exist for Node.js, Go, Python, React, React Native and vanilla JavaScript, and a dashboard handles user administration. Least vendor lock-in is an explicit goal, and leaving does not force your users to reset passwords or sign up again.

Ory Kratos lifts identity out of application code and puts it behind HTTP APIs. Login, registration, account recovery, verification and profile management become flows your services consume, rather than features every team rewrites once per product.

It is API first and interface agnostic, with both browser-based and native app flows, so any framework can drive it. Identity schemas and traits define what a user record holds, admin APIs cover lifecycle management, and the wider Ory stack adds OAuth2, OpenID Connect and access control when you need them.

Self-hosting is treated as a first-class path, not a courtesy.

• Platforms: installs on Linux, macOS, Windows and Docker, or builds from source.
• Databases: PostgreSQL, MySQL and CockroachDB are the supported stores.
• Kubernetes: deploying to Kubernetes and other orchestrators is covered in the install guide.
• Multi-factor: MFA belongs to the core flow set rather than arriving as an add-on.
• Migration path: pairing Kratos with Ory Hydra replaces the OAuth2 and OpenID Connect side of an existing provider while clients keep speaking the same protocols.

The open source distribution carries no license requirements and suits individuals, researchers and workloads that can live without an SLA. A managed equivalent runs the same server on the Ory Network, API compatible with what you would host yourself, for teams that would rather not operate identity infrastructure at all.

Positioned as an open source alternative to Auth0, Clerk, and Firebase Auth, Authgear is an extensible turnkey solution for consumer authentication needs. It removes the login stack nobody wants to build twice: signup pages, account settings, second factors, session revocation, and the audit trail an enterprise buyer will eventually ask about.

The repository carries four components: the Authgear server itself, AuthUI for login, registration and profile pages, a portal for managing project configuration, and an Admin API exposing a GraphQL interface over services and data. SDKs live in separate repositories, covering web JavaScript with Next.js, Vue, React and Angular, plus React Native, Capacitor, iOS, Android, Flutter, and Xamarin.

The out-of-the-box feature set targets SaaS products and multi-app ecosystems.

• Passwordless login: magic links and one-time passwords over email, SMS, or WhatsApp.
• Passkeys: an anti-phishing alternative to passwords, supporting FIDO2 hardware keys and password managers.
• Multifactor authentication: TOTP through Google Authenticator or Authy, email and SMS codes, and an extra password factor.
• Protocols and SSO: OIDC, OAuth 2.0, and SAML, with enterprise connections to ADFS and LDAP.
• Access control: roles and groups extend access management across the applications Authgear powers.
• Hooks and templates: webhooks and TypeScript hooks fire on events such as a new signup, while email and SMS templates localize per language.

A quick start guide carries tutorials for JavaScript, Go, PHP, Next.js, Laravel, and Spring. Self-hosting instructions cover local development, with a Helm chart as the recommended route to Kubernetes in production, and Authgear Cloud exists for teams who would rather not run it.