Auth0

Identity platform for authentication, authorization, SSO, and social login in apps.

Overview

Auth0 is a comprehensive authentication and authorization platform designed to secure users, AI agents, and machine identities across modern applications. It provides frictionless authentication experiences while maintaining enterprise-grade security, supporting passwordless login, social identity providers, and adaptive multi-factor authentication.

The platform is built to handle diverse use cases including B2C customer identity, B2B SaaS with enterprise SSO, AI agent identity and authorization, and machine-to-machine (M2M) authentication. Auth0 blocks over 800 billion attacks monthly and handles 23 billion authentications every month, with 99.99% uptime availability.

Developers can integrate Auth0 into any stack using 30+ SDKs and quickstarts across languages and frameworks. The platform includes specialized features for AI agents such as Token Vault for secure API access, fine-grained authorization for RAG pipelines, and human-in-the-loop controls via CIBA (Client-Initiated Backchannel Authentication).

Key features

Universal Login and Embedded Login
Single Sign-On (SSO)
Multi-factor Authentication (MFA)
Passwordless authentication
Fine-Grained Authorization (FGA)
Token Vault for API access management
Machine-to-Machine (M2M) authentication
SCIM provisioning
Bot detection
30+ SDKs and quickstarts

Pros

Quick integration in minutes with minimal code
Handles massive scale (10B authentications/month)
Comprehensive security with 3B+ attacks blocked monthly
Extensive SDK and framework support
Enterprise features available out of the box
99.99% uptime guarantee
Specialized support for AI agents and modern architectures

Cons

Pricing details not visible on public pages
Requires developer integration for implementation
Learning curve for advanced features like FGA
Dependency on third-party service for authentication

Use this if

You need a scalable, enterprise-grade authentication platform with support for modern architectures including AI agents, require SSO and advanced authorization controls, or want to reduce IAM development overhead.

Skip this if

You need a self-hosted solution, prefer open-source authentication systems, or require transparent pricing information before evaluation.

Best for

Securing user authentication in web and mobile appsImplementing single sign-on across applicationsProtecting AI agents and internal toolsB2B SaaS applications requiring enterprise featuresConsumer applications needing passwordless loginFine-grained access control and authorization

Alternatives

OktaAuth.jsKeycloakFirebase AuthenticationAmazon CognitoMicrosoft Entra ID

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