Comparison · Cybersecurity
SSO vs SCIM: enterprise identity for B2B SaaS
SSO handles authentication; SCIM handles provisioning. You need both for the enterprise identity story — here’s when and how.
The headline difference
SSO is about authentication: “prove who you are once, get into everything.” SCIM is about provisioning: “keep my user list in sync between the identity provider and the app.” One handles login; the other handles lifecycle.
Why you need both
| Problem | SSO solves | SCIM solves |
|---|---|---|
| Avoid password sprawl | Yes | No |
| Auto-create accounts on first login | JIT only | Yes — ahead of first login |
| Auto-deactivate on offboarding | Blocks login but app data persists | Yes — deactivates app account |
| Sync group/role changes | Sometimes (via OIDC claims) | Yes — reliably |
| Audit “who has access” | No | Yes |
Implementation order for B2B SaaS
1. OIDC SSO first. It’s the deal-blocker for enterprise. Implement against a generic OIDC provider; major IdPs work out of the box.
2. SAML 2.0 next. Required by older enterprises (especially Microsoft-shop F500). The protocol surface is larger but well-trodden.
3. SCIM after the first ten enterprise customers ask for it. Server-side SCIM is more work than SSO; do it once you have customers asking specifically about offboarding automation.
Managed-service shortcuts
If you don’t want to build either, WorkOS, Frontegg, Stytch, Auth0, and Clerk all offer drop-in SSO + SCIM with a unified developer experience. Pricing is per-organisation; below ten enterprise customers it’s cheaper to build, above twenty it’s cheaper to buy.
Frequently asked questions
What’s the difference between SSO and SCIM?
SSO (Single Sign-On) handles authentication — letting a user prove their identity once and access many apps. SCIM (System for Cross-domain Identity Management) handles provisioning — automatically creating, updating, and deactivating user accounts across apps when their record changes in the source-of-truth identity provider. You need both for a complete enterprise identity story.
If I have SSO, do I need SCIM?
Yes, if your app supports SCIM. SSO alone means new users still have to be manually created in your app before they can sign in; deactivated users in the IdP can still access your app until you manually delete them. SCIM closes both gaps.
Which SSO protocol should I implement?
OIDC (OpenID Connect) for new applications — it’s the modern, JSON-based standard built on OAuth 2.0. SAML 2.0 only if you must integrate with legacy enterprise IdPs that don’t support OIDC. Most modern IdPs (Okta, Azure AD, Auth0, JumpCloud) support both.
Is SCIM hard to implement?
Server-side SCIM is moderately complex — you need to expose REST endpoints for /Users, /Groups, schema discovery, and bulk operations, with idempotent semantics. Most SaaS apps add SCIM after SSO; many use a managed provider (WorkOS, Frontegg, Stytch) to offload the implementation.
Are SSO and SCIM only for enterprise customers?
Today, mostly. Enterprise buyers expect SSO + SCIM as table stakes for $50k+ ARR contracts — the “SSO tax” — and the absence of either disqualifies you from those deals. Smaller buyers rarely ask.