Stack Auth vs FusionAuth: Features, Pricing and User Reviews 2026
Stack Auth
Open-Source Authentication Platform for Developers

FusionAuth
Developer Authentication Platform

Stack Auth
Open-Source Authentication Platform for Developers

FusionAuth
Developer Authentication Platform

What are Stack Auth and FusionAuth?
Stack Auth is a complete authentication solution that handles all the complex parts of user login and management. When you add it to your application, you get ready-made login pages, account settings, password reset flows, and user dashboards without writing code for these features yourself.
The platform supports multiple ways for users to sign in, including regular passwords, social logins through Google or GitHub, magic email links, and modern passkeys using fingerprints or face recognition. It also handles advanced features like two-factor authentication for extra security, team management for business apps, and permission systems to control what different users can do.
Stack Auth is fully open-source and licensed under MIT and AGPL, meaning you can see exactly how it works and modify it if needed.
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 Stack Auth and FusionAuth
Password, OAuth, and magic link authentication
Two-factor authentication and passkeys
Team and organization management
Role-based permissions and access control
Pre-built React components and UI
User impersonation for support
Webhooks and real-time notifications
Custom email templates
REST API for integrations
Open-source and self-hostable
Next.js, React, JavaScript support
Admin dashboard for user management
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 Stack Auth and FusionAuth
Pricing of Stack Auth and FusionAuth
Stack Auth offers transparent pricing that scales with your needs. The Free plan is perfect for individuals and small projects, supporting up to 10,000 users with unlimited projects and teams. You get one dashboard administrator and access to all core authentication features.
The Team plan costs $49 per month and increases your user limit to 50,000 users. It includes three dashboard administrators, with additional admins available at $49 each. This plan is ideal for early startups and small teams building their products.
The Growth plan at $299 per month removes all user limits entirely. You get unlimited users, projects, and teams, along with five dashboard administrators included. Additional admins cost $49 each. This plan is designed for growing businesses that need to scale without worrying about user count restrictions.
All plans include the same core features, with the main differences being user limits and admin accounts.
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: Stack Auth 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
Auth.js
Free Open-Source Authentication Library
Auth0
Secure Authentication & User Login Platform by Okta
Better Auth
Free TypeScript Authentication
WorkOS
Enterprise Authentication for Developers
Okta
Cloud Identity and Access Management Platform
MojoAuth
Secure Passwordless Authentication for Web and Mobile Apps