FusionAuth
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
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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Boilerbay
Boilerbay presents a robust Next.js SaaS package aimed at accelerating the creation and launch of software-as-a-service applications. This starter kit features pre-built landing and waitlist pages, as well as crucial functionalities such as user authentication with NextAuth.js, database management via Prisma, email services from Resend, and Stripe for payment processing. Developers have the flexibility to personalize the theme and design using Tailwind CSS and Shadcn UI components, ensuring their applications reflect unique brand identities. Additionally, the platform accommodates AI integrations, including OpenAI and Pinecone, which allow the implementation of sophisticated features such as AI-generated content and interactive chatbots. Comprehensive documentation is available to guide users through the setup and deployment processes, with deployment options that include popular platforms like Vercel. Furthermore, Boilerbay’s focus on user experience ensures that developers can seamlessly navigate and utilize the tools provided, making it an attractive choice for those looking to build SaaS solutions efficiently.
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Nextacular
Nextacular is an open-source starter kit crafted to accelerate the creation of full-stack, multi-tenant SaaS applications. Utilizing modern technologies such as Next.js, Tailwind CSS, and Prisma, it presents a comprehensive set of features designed to simplify the development journey. Among its offerings are authentication mechanisms using magic links and social logins facilitated by NextAuth, as well as seamless database integration with relational databases like PostgreSQL and MySQL. The kit also supports multi-tenancy, enabling service to multiple customers across various subdomains or bespoke domains from a single, unified codebase. Furthermore, Nextacular incorporates functionality for teams and workspaces, enabling users to easily invite colleagues to collaborate within designated workspaces. In addition, the platform features a customizable landing page, efficient billing and subscription management via Stripe integration, and versatile design components crafted with Tailwind CSS that can be adapted to fit your unique design system. With these capabilities, Nextacular empowers developers to focus on building innovative solutions without getting bogged down in repetitive setup tasks.
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