SAML vs. OAuth: What’s the Difference?

Last updated on January 7, 2026

The main difference between SAML and OAuth is that SAML is mainly an authentication protocol that grants you access to applications, while OAuth is an authorization protocol that determines what you can and cannot do once you access an application.

What is SAML?

SAML (Security Assertion Markup Language) is an open standard used for single sign-on (SSO), allowing users to access multiple applications with one set of login credentials. It enables secure identity federation between identity providers (IdPs) and service providers (SPs), often used in enterprise authentication.

Note on authorization: While SAML is primarily an authentication protocol, the SAML assertion may include user attributes (such as roles and permissions), as well as specific authorization assertions (AuthorizationDecisionStatement) that the service provider (SP) can use to make access decisions.

What is OAuth?

OAuth (Open Authorization) is a secure authorization protocol that allows users to grant third-party applications limited access to their resources without sharing login credentials. It powers secure logins and delegated access in platforms like Google, Facebook, and Microsoft services.

Note on authentication: OAuth itself does not authenticate a user’s identity. Its purpose is to authorize access. When you see options like “Sign in with Google” or “Allow this application to access your account,” OAuth 2.0 operates behind the scenes to grant permissions. For actual identity verification, a layer like OpenID Connect is used, which extends OAuth to include authentication and user identity details.

SAML vs. OAuth: What’s the Difference?

The following table depicts the major differences between SAML and OAuth.

Aspect	SAML	OAuth
Full Name	Abbreviation of Security Assertion Markup Language	Short for Open Authorization
Standard	Standard described by OASIS	Standard described in RFC 6749
Data Format	Based on Extensible Markup Language (XML)	Format-agnostic; often used with JSON (e.g., in OpenID Connect)
Message Security	SAML responses can be digitally signed and encrypted	OAuth does not provide message encryption on its own. The security of data transmission depends on the use of a secure channel, most often TLS
Token Format	SAML defines a token format	OAuth does not define a token format. It’s up to the implementation (e.g., bearer tokens, JWTs)
Primary Use Case	SAML is explicitly designed for federated SSO	OAuth was not designed for authentication or SSO, but is often used as a basis for SSO when extended with OpenID Connect (OIDC)

Practical Examples of OAuth and SAML

To illustrate how these protocols serve distinct real-world needs, here are some concrete scenarios.

SAML in Action:

• Used for enterprise Single Sign-On (SSO) across security domains, e.g., employees log into Salesforce through Microsoft Entra ID (Azure AD) using a SAML assertion.
• Enables federated identity via open-source tools like Shibboleth, commonly used in academic and public-service federations for seamless cross-domain authentication.
• Allows integrating multi-factor authentication into cloud apps.

OAuth in Action:

• Powers social login flows. Users start an app and are prompted with “Log in with Google/Facebook,” granting limited API access without sharing passwords.
• Delegates access securely: financial tools (e.g., budgeting apps) use OAuth to let third-party apps access user banking data with explicit consent, without exposing credentials.

Advantages of SAML over OAuth

1. Designed for enterprise-level Single Sign-On (SSO): SAML facilitates seamless authentication across corporate applications, enabling users to log in once and access multiple systems. It’s widely adopted in regulated sectors.
2. Strong security via signed (and optionally encrypted) XML assertions: In typical IdP/SP deployments, SAML assertions and responses are digitally signed (with XML Signature) and encrypted (with XML Encryption), which provides strong guarantees of integrity, authenticity, and confidentiality. OAuth tokens (such as JWT) can also be signed; however, this is not explicitly enforced by the specification.
3. Ideal for cross-domain federation and legacy systems: It excels in federated identity use cases, enabling identity providers and service providers to interoperate securely.

Advantages of OAuth over SAML

1. Optimized for delegated authorization: OAuth allows third-party applications to access user resources without requiring user credentials, making it perfect for API-driven and consumer-facing contexts.
2. Lightweight and flexible with JSON tokens: OAuth’s use of simple, JSON-based access tokens makes it more efficient for mobile and modern web architectures.
3. Better suited for API-first platforms and dynamic apps: Its versatility enables granular, revocable access via scopes and token expiration, providing fine-tuned control over permissions.

SAML vs. OAuth: Which One to Choose?

SAML and OAuth are not mutually exclusive. Most modern businesses need authentication and authorization, and some of them employ both SAML and OAuth for these purposes.

• Choose SAML when:
  • You need robust enterprise Single Sign-On (SSO) across internal or SaaS applications, especially in regulated environments like finance, healthcare, or government.
  • You require signed, XML-based assertions for authentication, ensuring integrity and support for legacy systems and federation standards.
  • You need to enable multi-factor authentication on logins to an application and this application supports SAML.
• Choose OAuth when:
  • Your architecture is API-first, mobile-focused, or client-heavy, and you need to grant delegated access without exposing user credentials.
  • You require flexibility with JSON tokens and scoped permissions, enabling efficient token management, revocation, and fine-grained authorization control.

SAML vs. OAuth: Summary

SAML answers “Who are you?”; OAuth answers “What are you allowed to do?”.

While SAML is an XML-based standard primarily used for authentication and Single Sign-On (SSO), OAuth is an authorization framework that is format-agnostic and commonly used with JSON-based tokens like JWT. The two differ in focus, implementation format, message handling, and typical use cases. SAML was designed for federated identity, whereas OAuth was optimized for delegated access to APIs.

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