Auth.js vs FusionAuth: Features, Pricing and User Reviews 2026
FusionAuth
Developer Authentication Platform
FusionAuth
Developer Authentication Platform
What are Auth.js and FusionAuth?
Auth.js is a complete authentication solution that works across different JavaScript frameworks. It provides everything needed to add secure login systems to websites and applications. You can let users sign in through their existing accounts on services like Google or GitHub, or you can use email-based magic links, or even traditional username and password combinations.
The library is runtime agnostic, meaning it adapts to work with Next.js, SvelteKit, Express, Qwik, and other frameworks. It handles session management, protects routes, and connects to databases when needed. Auth.js follows web standards and security best practices, making it both safe and reliable. Since it is open source, the code is publicly available for review and contributions from developers worldwide.
FusionAuth is a complete authentication system that manages who can access your application and what they can do. You can install it on your own computer, your company servers, or use their cloud service. This flexibility makes it different from most authentication tools that force you to use only their cloud.
The platform supports all modern login methods - traditional passwords, passwordless access, social media logins, and biometric authentication like fingerprints. It follows industry standards like OAuth2, OpenID Connect, and SAML, meaning it works smoothly with other software.
There is a free version with all core features, and paid plans add extra security, support, and cloud hosting. The free version has no user limits, making it suitable for projects of any size.
Features of Auth.js and FusionAuth
OAuth 2.0 and OpenID Connect support
80+ pre-configured authentication providers
Magic link email authentication
Username and password credentials
WebAuthn passwordless login
Multiple framework support (Next.js, SvelteKit, Express)
Database adapters for major databases
JWT or database sessions
Built-in security features
Custom page support
TypeScript ready
Open source and free
Password and passwordless authentication options
Social login integration (Google, Facebook, Apple, LinkedIn)
Single sign-on across applications
Multi-factor authentication and biometric support
Breached password detection
User registration and profile management
Role-based permissions and access control
REST APIs and SDK libraries
Self-hosted or cloud deployment
Customizable login pages and email templates
Use Cases of Auth.js and FusionAuth
Pricing of Auth.js and FusionAuth
Auth.js is completely free to use with no pricing tiers or hidden costs. As an open-source project, it is licensed under the ISC license, which allows anyone to use, modify, and distribute the software freely for both personal and commercial projects.
There are no subscription fees, no usage limits, and no charges for any features. All capabilities, including support for unlimited providers, database integrations, and advanced security features, are available at no cost. This makes Auth.js an excellent choice for projects of any size, from small personal websites to large enterprise applications.
The project is maintained by a community of contributors and is now part of Better Auth Inc. Developers can contribute to the project, report issues, and access community support through GitHub discussions completely free of charge.
FusionAuth offers flexible pricing to match different needs and deployment preferences.
Self-Hosted is completely free with unlimited users. Download and run FusionAuth on your own infrastructure with no ongoing costs. You get all core authentication features, making it perfect for development, testing, and production environments where you want full control.
Basic Plan starts at $37 per month and provides a single cloud server instance, ideal for development and testing environments. It includes one custom domain and basic cloud hosting.
Business Plan costs $225 per month and offers a dedicated server with nightly backups, availability across multiple zones, and support for up to five custom domains. This plan suits most production applications.
High Availability Plan begins at $500 per month with redundant servers, configurable backups, and up to 99.99% uptime guarantee with the Enterprise support plan. This includes 20 custom domains and deployment in any AWS region.
FAQs: Auth.js vs FusionAuth
Reviews: Auth.js vs FusionAuth
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Compare FusionAuth With Other Tools
Kinde
Simple Authentication and User Management for Developers
Clerk
Complete Authentication for Modern Apps
Logto
Open-Source Authentication Platform with SSO and RBAC
Stack Auth
Open-Source Authentication Platform for Developers
Auth0
Secure Authentication & User Login Platform by Okta
Better Auth
Free TypeScript Authentication
WorkOS
Enterprise Authentication for Developers
Okta
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MojoAuth
Secure Passwordless Authentication for Web and Mobile Apps