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SAML versus OpenID Connect: Choose the right SSO protocol

To set up single sign-on (SSO) with Microsoft Entra ID, you choose between two protocols: Security Assertion Markup Language (SAML) 2.0 and OpenID Connect (OIDC). This article explains how the two protocols differ, when to use each, and how to choose for your app.

Why your protocol choice matters

Your protocol choice shapes how you build the app, how hard it is to integrate, and how well it fits your customers' environments. Microsoft Entra ID fully supports both protocols, but each one suits different needs.

The choice affects two roles:

  • Independent software vendor (ISV) application developers: It drives development effort, framework support, and how easily you meet varied customer requirements.
  • IT administrators: It affects how well an app fits your identity infrastructure and security policies.

What is SAML 2.0?

SAML 2.0 is a mature federation protocol based on XML. Enterprises have used it widely for over a decade. SAML safely shares sign-in and access data between identity providers and apps.

SAML uses XML messages and assertions to carry sign-in data. It maps user attributes in detail. It also supports complex enterprise needs, such as signed XML assertions and detailed attribute statements.

What is OpenID Connect (OIDC)?

OpenID Connect (OIDC) is a modern sign-in protocol built on OAuth 2.0. It uses JSON tokens called JSON Web Tokens (JWTs) and REST APIs. OIDC signs users in, and OAuth 2.0 handles access.

OIDC is simpler and more developer-friendly. It fits modern app designs, including single-page applications, mobile apps, and microservices.

Comparing SAML and OIDC

The following table compares SAML 2.0 and OpenID Connect across the factors that matter most for SSO integration.

Aspect SAML 2.0 OpenID Connect
Message format XML-based JSON-based
Token type XML assertions JWT tokens
Enterprise adoption Widely established Growing rapidly
Developer experience Complex, requires XML handling Simpler, REST-based
Development complexity Higher, XML processing required Lower, REST/JSON based
Modern frameworks Limited native support Excellent support
Mobile/SPA support Challenging Native support
Validation alignment Good, established patterns Excellent, modern standards
Multi-tenant SaaS suitability Adequate with complexity Native, optimal
Customer onboarding effort More complex, manual setup Simpler, automated discovery
Long-term maintainability Higher overhead Lower maintenance
Attribute handling Rich XML attribute statements JSON claims
Security features XML signatures, complex controls JWT signatures, OAuth scopes

Decision summary

Both protocols are secure, and Microsoft Entra ID fully supports each one. The preceding table compares them aspect by aspect, so use it for the detailed differences. This summary highlights why an ISV picks each protocol: OIDC suits new, cloud-native SaaS and customers with modern identity, while SAML is a requirement-driven choice for enterprise customers, compliance or procurement mandates, or legacy identity providers that support only SAML. Support both protocols when your customer base spans both worlds.

Choose OpenID Connect (OIDC) if you:

  • Build new SaaS or cloud-native apps
  • Build single-page applications (SPAs) or mobile apps
  • Want development speed and modern integration
  • Serve customers with modern identity systems
  • Plan for multitenant, scalable distribution

Choose SAML if you:

  • Have enterprise customers that require SAML
  • Work with legacy identity providers that lack OIDC
  • Must meet compliance or procurement rules that mandate SAML
  • Already have a working SAML implementation

Support both protocols if you:

  • Serve mixed customer environments that need both
  • Want the widest compatibility across organizations

If unsure, default to OIDC for new SaaS development. OIDC fits modern apps, Microsoft Entra validation, and today's enterprise trends.

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