SAML vs OAuth.
SAML (Security Assertion Markup Language) is an authentication + single-sign-on standard — it lets an identity provider assert "this is who the user is" to a service provider using a signed XML assertion. OAuth 2.0/2.1 is an authorization framework — it issues access tokens that let an application call an API on a user's behalf. SAML answers "who is the user, and can they log in here?"; OAuth answers "what is this app allowed to access?" They are not competitors — many systems use both.
SAML vs OAuth 2.x.
| Dimension | SAML | OAuth 2.x |
|---|---|---|
| Primary purpose | Authentication + SSO | Authorization (delegated access) |
| Format | XML assertions | JSON + bearer/DPoP tokens |
| Era / style | Enterprise SSO (2005-era), browser-redirect | API + mobile (2012-era), token-based |
| Carries | Identity + attributes (the assertion) | Scopes (what the client may do) |
| Typical use | Employee logs into a SaaS app via corporate IdP | App calls an API / "allow access to your data" |
| Identity layer | Built in | Added by OIDC on top of OAuth |
Why they get compared (and why it is the wrong comparison)
SAML and OAuth get pitted against each other because both appear in "how do I log users in?" conversations — but they were built for different jobs. SAML is an authentication + federation standard: it exists to let one organization's identity provider vouch for a user to another organization's application (classic enterprise SSO). OAuth is an authorization framework: it exists to let a user grant an application scoped access to a resource without sharing a password.
The honest comparison is SAML vs OIDC (both authenticate), or OAuth vs nothing (it is the authorization layer). OAuth alone does not authenticate — using a raw OAuth access token as proof of login is the classic security mistake. OpenID Connect adds the authentication layer on top of OAuth, which is why "SAML vs OIDC" is usually the real decision for new SSO.
In practice, you often use both
A workforce user might authenticate to your app via SAML (corporate IdP SSO), and that same app might use OAuth to call a downstream API on the user's behalf. They are layers, not alternatives. The 2026 guidance: for new SSO choose OIDC over SAML (JSON, mobile-friendly, the modern default), keep SAML where the enterprise integration already exists, and use OAuth scopes for API authorization regardless.
When to use each.
Reach for SAML when…
- You need enterprise SSO and the other side only speaks SAML.
- You are integrating with legacy enterprise apps / IdPs.
- The integration already exists and works (don't rebuild it for fashion).
Reach for OAuth (+ OIDC) when…
- You need API authorization / delegated access (OAuth).
- You need authentication for a new app, mobile, or SPA (OIDC on OAuth).
- You want the modern, JSON-based, token-native default.
Common questions.
Is SAML more secure than OAuth?+
Neither is "more secure" — they do different jobs. SAML handles authentication/SSO; OAuth handles authorization. Security depends on correct implementation (signed + audience-restricted SAML assertions; sender-constrained, audience-validated OAuth tokens). The real insecurity is misusing OAuth as an authentication mechanism without OIDC.
Should I use SAML or OAuth for single sign-on?+
For SSO specifically, the modern choice is SAML vs OIDC (OIDC is OAuth + authentication). OAuth by itself is not an SSO/authentication protocol. New builds favor OIDC; SAML persists in established enterprise integrations.
Can SAML and OAuth work together?+
Yes, and they frequently do. A user can authenticate via SAML SSO while the application uses OAuth to obtain scoped access to APIs. They operate at different layers — authentication vs authorization — and compose cleanly.
The whole picture, in one place.
This explainer is part of our complete guide to IAM — authentication, authorization, governance, privileged access, the standards, and how to run a program.