FusionAuth is the authentication and authorization platform engineered for developers who demand flexibility and control. Built from the ground up to integrate with any stack, every feature — from user registration to MFA and SSO — is exposed via a modern, well-documented API.
Support for every major identity protocol is included out of the box: OIDC, SAML, OAuth2, JWT, passwordless login, social sign-on, and more. Whether you’re building a greenfield app or retrofitting auth into a legacy system, FusionAuth adapts to your use case — not the other way around.
Need compliance? FusionAuth helps you meet GDPR, HIPAA, and COPPA standards quickly and reliably.
Deploy it your way: install on Linux, Windows, macOS, Docker, or Kubernetes — or go with FusionAuth Cloud, our managed SaaS hosting. No black boxes. No vendor lock-in. Just powerful, customizable auth that works the way you do.
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Auth0 takes a modern approach to Identity and enables organizations to provide secure access to any application, for any user. Auth0 is highly customizable, and simple yet flexible. Safeguarding billions of login transactions each month, Auth0 delivers convenience, privacy, and security so customers can focus on innovation.
With Auth0, you can rapidly integrate authentication and authorization for web, mobile, and legacy applications, with new Fine Grained Authorization (FGA) that goes beyond role-based access control.
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Auth Armor
You can harness the power of biometrics to make authentication simple for any website or application. This will allow you to create a new way to log in and authenticate online. You can authenticate your users using their smartphones with 2-factor and passwordless authentication. Auth Armor provides secure authentication for every user. It does not require weak passwords or complicated codes. We have created powerful APIs, SDKs and libraries that allow you to create what you want, however you want it. You can use our tools to add authentication to any app using any flow. We offer protection for workers and consumers, so you have the power and flexibility you need to secure any information. Auth Armor is the most efficient mobile authentication system available. Instant push messaging is available to users' devices, enabling them to log in and authenticate quickly.
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Scalekit
Scalekit is an authentication and integration platform designed specifically for AI agents that need to securely connect with SaaS applications, APIs, MCP servers, databases, and internal systems. The platform enables agents to act on behalf of individual users instead of using shared service accounts, ensuring every action follows the user's identity, permissions, and approved access scopes. Scalekit manages delegated OAuth authentication, secure credential vaulting, token lifecycle management, authorization checks, and API communication without requiring developers to build that infrastructure themselves. Developers can connect to more than 100 prebuilt integrations or create custom connectors for proprietary services and internal APIs. Built-in handling for pagination, retries, rate limiting, and error management simplifies tool execution while improving application reliability. Every request is logged with a complete delegation chain that records the user, agent, connector, permissions, and resulting actions for auditing and compliance. The platform supports encrypted credential storage, regional deployments, private cloud options, SIEM integrations, and enterprise-grade security controls. Scalekit also extends beyond AI agents by providing SaaS authentication capabilities such as SSO, SCIM provisioning, RBAC, passwordless authentication, and user management. By combining delegated identity, secure authentication, and production-ready connector infrastructure, Scalekit enables organizations to build trustworthy AI agents without the complexity of managing authentication themselves.
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