What should I use for SAML vs OIDC in a SaaS app?

For a SaaS app, the default recommendation is:

• Use OIDC (OpenID Connect) for new integrations and product authentication.
• Support SAML if you need to sell into enterprise customers who already require it.

Quick rule of thumb

Choose OIDC when:

• You’re building a modern SaaS product
• You want easier implementation and debugging
• You need mobile, SPA, or API-friendly auth
• You care about better developer experience
• You want cleaner support for MFA, token-based flows, and modern identity providers

Choose SAML when:

• You’re targeting enterprise SSO
• Your customers use older IdPs or have SAML as a procurement requirement
• You need compatibility with corporate identity systems like legacy ADFS setups
• Security teams explicitly ask for SAML in vendor reviews

Practical SaaS recommendation

Most SaaS companies do this:

1. Primary auth: email/password, social login, or OIDC-based login
2. Enterprise SSO option: support both OIDC and SAML
3. Internally: if you have to pick one for customer SSO, prefer OIDC unless a customer insists on SAML

Why OIDC is usually better for SaaS

• Built on OAuth 2.0 and easier for app + API ecosystems
• Simpler token model
• Better for single-page apps and mobile apps
• Usually less painful to implement and maintain
• Better fit for modern identity providers like Okta, Auth0, Azure AD / Entra ID, Google Workspace, etc.

Why SAML still matters

• Very common in enterprise procurement
• Many large companies already have SAML infrastructure and policies
• Some IdPs and security teams are more comfortable with it
• If you don’t support SAML, you may lose deals

Common enterprise pattern

If your SaaS serves businesses, a good approach is:

• OIDC first
• SAML support for enterprise plan
• Offer Just-In-Time provisioning and/or SCIM alongside SSO
• Allow domain-based routing to the customer’s IdP

Bottom line

If you’re asking which to build first for a SaaS app:

Build OIDC first. Add SAML if you sell to enterprises.

If you want, I can also give you:

• a decision matrix
• a technical architecture recommendation
• or a list of pitfalls when implementing SAML/OIDC