OAuth 2.0 / OIDC vs SAML 2.0
A detailed comparison of features, privacy, and developer experience.
Last reviewed: 2026-05-17
Executive Summary
Build new things with OIDC. Support SAML when enterprise customers demand it, and they will, eventually.
OAuth 2.0 / OIDC
OAuth 2.0 is an authorization framework; OpenID Connect (OIDC) adds authentication on top. JSON over HTTPS, bearer tokens, designed for APIs and modern apps.
SAML 2.0
Security Assertion Markup Language, an older XML-based standard for SSO. Dominant in enterprise (Okta, AD FS, Workday), still required for many B2B integrations.
Editor's Verdict
For greenfield apps, OIDC is the right default: it's JSON over HTTPS, well-supported by every framework, designed for both web and mobile, and the OIDC flows (PKCE, device, client credentials) cover modern app shapes. SAML is XML, ships browser POST redirects through hidden forms, and its assertions are a security minefield (signature wrapping attacks, XML canonicalization bugs). But: enterprise IdPs (Okta, Azure AD, OneLogin, ADFS) all speak SAML, and your largest B2B customers will eventually ask for it. The pragmatic stack: implement OIDC primarily, add SAML when a paying enterprise asks (often via an identity broker like WorkOS or Auth0 that handles the SAML side for you). Don't roll your own SAML SP, use a library or a broker.
What we ran
These are protocols, not buttons on this site. OAuth 2.0 / OIDC is what the OAuth debugger and JWT tools help you inspect (bearer tokens). SAML is XML assertions your IdP posts. If the artifact in your ticket is a JWT, you are in OAuth/OIDC, not SAML.
🔓When to use OAuth 2.0 / OIDC
- Greenfield consumer or B2B SaaS apps
- Mobile and SPA flows (PKCE is built for them)
- Anything where you'd rather work with JSON than XML
🏢When to use SAML 2.0
- Enterprise customer mandates SAML for SSO (Okta, ADFS, etc.)
- Existing SAML IdP and you're the new SP in their ecosystem
- Compliance auditor specifically requires SAML
| Feature | OAuth 2.0 / OIDC | SAML 2.0 |
|---|---|---|
| Wire format | JSON | XML |
| Transport | HTTPS REST | HTTP POST / Redirect Binding |
| Mobile / SPA support | First-class (PKCE) | Awkward |
| Authentication | Via OIDC layer | Built in |
| Authorization scopes | First-class | Attributes |
| Token format | JWT or opaque | Signed XML assertion |
| Common implementations | Auth0, Clerk, Cognito | Okta, ADFS, OneLogin |
| Enterprise adoption | Growing | Dominant |
Key Takeaways
- OAuth/OIDC: JSON + JWT, lightweight, designed for APIs and mobile/SPA. Dominant for new builds.
- SAML: XML, enterprise-rooted, baked into legacy SSO products; required by many large customers.
- OIDC is OAuth 2.0 + identity layer, the modern 'login with Google/Microsoft/Okta' pattern.
- If you sell to enterprise, you'll eventually need SAML, not optional in many RFPs.
- Build OIDC first; add SAML when an enterprise customer's procurement requires it.
Common Mistakes
- Building SAML for a B2C product, overkill; OIDC is simpler and matches every consumer identity provider.
- Implementing SAML by hand, the XML signing rules are nuanced; use a battle-tested library (Auth0, WorkOS, etc.).
- Confusing OAuth (authorization) with OIDC (authentication), using bare OAuth for login is the original sin.
- Forgetting that SAML supports both SP-initiated and IdP-initiated flows, implementing only one breaks enterprise customers.
Frequently Asked Questions
If I implement OIDC, do I get SAML for free?+
No. They're different protocols. But if you use an identity broker (WorkOS, Auth0, Stytch), you implement OIDC against the broker and they handle the SAML translation to enterprise IdPs.
Why is SAML still around?+
Enterprise IT bought into it 10–15 years ago. Migrating an org's IdP is huge, so SAML persists. New enterprise products still need to speak it to enter most B2B markets.
What actually goes wrong when people hand-roll SAML?+
Two classic failures. XML signature wrapping: the assertion is signed, but the parser reads a different (attacker-injected) element than the one the signature covers, so an unsigned assertion is trusted. And missing audience/recipient validation: the SP accepts an assertion that was minted for a different service. Both are the reason the standard advice is to use a vetted library or an identity broker and never parse the XML yourself.
SCIM keeps coming up next to SAML — is it the same thing?+
No. SAML (or OIDC) handles the login; SCIM handles user provisioning — creating, updating, and deactivating accounts in your app when the customer's IdP admin changes them. Enterprise buyers usually want both: SSO so employees can log in, SCIM so a departing employee loses access automatically. They are separate implementations.
How we tested this
We evaluated both OAuth 2.0 / OIDC and SAML 2.0 in real developer workflows to build this comparison. Our assessment covers feature parity, privacy posture, developer experience, and ecosystem maturity.
Why these tools are worth your time
Privacy-respecting picks
We prefer tools that run locally or are explicit about what they send to the cloud.
Daily-driver tested
Recommendations come from real developer workflows, not marketing pages.
No vendor lock-in advice
We surface the trade-offs so you can switch later without rewriting your stack.