## Documentation Index

Fetch the complete documentation index at: [/llms.txt](/content/llms.txt)

Use this file to discover all available pages before exploring further.

In authentication, a user or application proves they are who they say they are by providing valid credentials. The most common verification is password, often combined with other methods, such as a fingerprint. Auth0 simplifies the use of open industry standards like OAuth 2.0, OIDC, and SAML to authenticate. Users can log into your applications with social media credentials, corporate accounts, and a broad range of other credentials.

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## Add Login

##### Implement Auth0 Universal Login (or an alternative) to control access to your applications.

[**Login** \\
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Choose from a variety of user login options.](/content/docs/authenticate/login/index.html)

[**Single Sign-On** \\
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Enable users to log in to one application and automatically authenticate in other applications.](/content/docs/authenticate/single-sign-on/index.html)

[**Passwordless** \\
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Let users enter mobile phone numbers or email addresses and receive a one-time code or link to log in without a password.](/content/docs/authenticate/passwordless/index.html)

[**Custom Token Exchange** \\
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Learn about Custom Token Exchange Early Access features.](/content/docs/authenticate/custom-token-exchange/index.html)

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## Provision Users

##### Source users from social identity providers (such as Facebook or SalesForce), enterprise user stores (such as Active Directory or Google Workspace), a custom database, and more.

[**Identity Providers** \\
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Set up sources of user accounts to authenticate your applications and APIs.](/content/docs/authenticate/identity-providers/index.html)

[**Database Connections** \\
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Authenticate users with an email/username and password and save their credentials in an Auth0-provided user store or in your own database.](/content/docs/authenticate/database-connections/index.html)

[**Enterprise Connections** \\
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Authenticate users with external, federated identity providers such as Azure AD, Google Workspace, and PingFederate.](/content/docs/authenticate/enterprise-connections/index.html)

[**Protocols** \\
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Easily implement open industry-standard protocols like OAuth 2.0, SAML, and LDAP for authentication and authorization.](/content/docs/authenticate/protocols/index.html)

[**Connection Settings Best Practices** \\
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Review best practices when configuring social and database connections.](/content/docs/authenticate/connection-settings-best-practices/index.html)