Best Auth0 Alternatives in 2026 (Open Source & Free)

While Auth0 is a widely recognized giant in the identity and access management (IAM) space, many organizations eventually seek alternatives due to its steeply scaling pricing tiers and vendor lock-in. As monthly active users (MAUs) grow, proprietary licensing and restricted features on lower tiers can strain budgets, prompting developers and business leaders to turn to customizable, self-hosted open-source solutions. By transitioning to open-source alternatives, teams can regain complete control over their user data, avoid unpredictable overage costs, and customize their authentication pipelines without limitations.

Name	Key Focus	Self-hosted support	License
Keycloak	Enterprise IAM & User Federation	Yes	Apache-2.0
Logto	Developer-centric Auth & Modern UI Components	Yes	AGPL-3.0
SuperTokens	Developer-friendly Session & User Auth	Yes	Apache-2.0
authentik	Flexible Identity Provider & SSO Integration	Yes	GPL-3.0
Supabase	Backend-as-a-Service (Postgres + Auth)	Yes	Apache-2.0

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Keycloak

• Core Features: Keycloak is an industry-standard Identity and Access Management (IAM) solution. Built in Java, it provides out-of-the-box support for user federation (like LDAP and Active Directory), single sign-on (SSO), social logins, multi-factor authentication (MFA), and fine-grained authorization policies.
• Main differences compared to Auth0: Unlike Auth0, which charges aggressively as your Monthly Active Users (MAUs) scale, Keycloak is fully open-source under the Apache-2.0 license and runs entirely on your infrastructure with no artificial pricing caps. However, Keycloak presents a much steeper learning curve, lacks Auth0’s lightweight modern SDK setup, and has a significantly higher memory footprint.
• Best use-case scenario: Keycloak is best suited for established enterprise environments that require robust user federation with legacy identity directories and need to comply with strict, on-premises data governance standards.
• Installation complexity: Complex

Logto

• Core Features: Logto is designed as a direct, developer-centric alternative to Auth0 and Clerk. Written in TypeScript, it offers modern authentication workflows, detailed user management, multi-factor authentication (MFA), single sign-on (SSO), and highly polished, ready-to-use login UI components out of the box.
• Main differences compared to Auth0: Logto focuses intensely on modern developer ergonomics and rapid integration. It streamlines the onboarding process by eliminating the complex interface configurations common in Auth0, replacing them with highly intuitive administrative dashboards and beautiful, pre-built frontend widgets. However, because it is released under the AGPL-3.0 license, compliance teams must carefully evaluate copyleft implications when integrating its source code directly into proprietary pipelines.
• Best use-case scenario: It is ideal for modern fast-moving startups and SaaS platforms that need to implement secure, beautiful, and fully functional authentication experiences in minutes without dedicating significant design and engineering hours.
• Installation complexity: Simple

SuperTokens

• Core Features: SuperTokens is an Apache-2.0 licensed open-source alternative written in Java and TypeScript. It offers self-hosted user authentication, secure session management, social login options, passwordless login, multi-factor authentication (MFA), and granular access control.
• Main differences compared to Auth0: SuperTokens fundamentally differs from the monolithic architecture of Auth0 by splitting its deployment into a backend core service combined with custom frontend and backend SDKs. This highly decoupled design provides developers with exceptional control over session states, cookies, and database operations, circumventing the complex multi-tenant environment management challenges often encountered when using Auth0. This architecture ensures high performance and security.
• Best use-case scenario: It is the optimal solution for engineering teams that demand programmatic control over their application’s session lifecycle, security architectures, and customized authentication API endpoints.
• Installation complexity: Medium

authentik

• Core Features: authentik is an open-source Identity Provider (IdP) written in Python and Go, focused on infrastructure flexibility. It supports single sign-on (SSO), multi-factor authentication (MFA), complete user management, and seamless compatibility with active directory frameworks.
• Main differences compared to Auth0: While Auth0 approaches identity from an application developer’s perspective, authentik is engineered with system administrators and DevOps teams in mind. It uses a robust, visual stage-and-flow planner that allows administrators to map out highly complex, customized login sequences. Unlike Auth0, which requires custom code via Auth0 Actions for non-standard behaviors, authentik provides these via an adaptable, built-in policy engine.
• Best use-case scenario: It is the premier choice for organizations managing a massive, heterogeneous suite of internal tools, homelabs, or corporate services requiring a centralized, flexible SSO solution.
• Installation complexity: Medium

Supabase

• Core Features: Supabase is a highly popular open-source Backend-as-a-Service (BaaS) written in TypeScript under the Apache-2.0 license. It packages a robust PostgreSQL database, user authentication (auth), file storage, edge functions, and real-time database subscriptions.
• Main differences compared to Auth0: Unlike Auth0, which acts as a dedicated, siloed identity management provider, Supabase treats authentication as a deeply integrated layer of your primary database. Because your user records live directly within your own PostgreSQL instance, you avoid the cumbersome data synchronization, webhooks, and latency issues commonly experienced when coordinating external SaaS identity providers with your app’s core database.
• Best use-case scenario: Supabase is the undisputed standard for greenfield projects and rapid application development where developers want a unified, open-source stack combining a database, file storage, and secure user auth out of the box.
• Installation complexity: Medium

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Decision Guide: How to Choose the Right One

Selecting the ideal open-source alternative depends heavily on your system architecture and deployment requirements. If you need a comprehensive, enterprise-grade identity provider with user federation, Keycloak is the industry standard despite its complexity. For modern web and mobile apps prioritizing rapid developer setup and polished UI components, Logto or SuperTokens are excellent options. If you are building an application from scratch and require database, storage, and auth capabilities bundled together, Supabase is the optimal choice. Finally, authentik serves best for administrators managing diverse internal services requiring flexible SSO flows.

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Moving away from Auth0’s scalable, developer-friendly ecosystem allows organizations to bypass costly MAU limits and regain control over their user data. Open-source alternatives have matured to match Auth0’s flexibility through various programming languages and licensing structures. By weighing deployment complexity against feature requirements, development teams can find a self-hosted alternative that aligns with both their technical architecture and long-term financial goals.

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Pricing and features verified as of 2026-06-25. Please refer to the official website for real-time updates.