How to Add Enterprise SSO to a Multi-Tenant SaaS Application

This article is a practical, step-by-step guide for implementing enterprise SSO in multi-tenant SaaS: model per-tenant IdP configuration, support SAML and OIDC, publish a single SP ACS endpoint, resolve tenant before redirecting to IdPs, validate assertions (signature, audience, expiry, InResponseTo, and replay protection), implement JIT provisioning and SCIM for deprovisioning, test with Okta/Microsoft Entra/Google Workspace, and consider a broker (SSOJet) to reduce per-IdP integration effort.