Buying SSO/IdP

Buyer's guide.

Overview

An identity provider is the load-bearing wall of every SaaS-heavy stack. Picking the wrong one is felt every day by every employee; picking the right one is invisible in the best way. The buying decision turns on protocol support, lifecycle automation, and how cleanly it scales from 50 employees to 5,000.

• Protocol support. SAML 2.0 and OIDC are non-negotiable; SCIM provisioning is the difference between a 5-minute onboard and a 50-minute one.
• Lifecycle automation. Joiner, mover, leaver flows triggered from HRIS; if employee onboarding still requires manual app access grants, the IdP is leaving value on the table.
• Compliance posture. SOC2, ISO 27001, FedRAMP if applicable; auditors increasingly want IdP audit logs as the source of truth for access reviews.
• Per-team operational fit. Admin UX, MFA flexibility, conditional access policies, and how painful it is to integrate the long-tail SaaS app no one warned you about.

The approach

Trial against your real app inventory. Vendors all support the popular apps cleanly; the long-tail SaaS that someone signed up for in 2022 is where integrations break.

• App inventory check. List every SaaS the company uses; confirm each vendor's connector library covers them or has a generic SAML/SCIM template.
• SCIM provisioning test. Onboard a real test user end-to-end; measure how many app grants happen automatically versus manually.
• Compliance evidence. Confirm audit log retention, access-review reporting, and IdP attestation reports are actually usable, not just present.
• Document the choice and the exit ramp. Capture rationale and how identity data and SAML configs would migrate if you switched.

Why this compounds

The right IdP keeps paying back: every new SaaS inherits SSO and provisioning, every employee onboard takes minutes instead of days, and access reviews stop being a quarterly nightmare.

• Security posture. Centralised authentication and provisioning shrink the surface for credential compromise.
• Operational consolidation. One identity surface across all SaaS removes per-app provisioning spreadsheets.
• Faster onboarding and offboarding. Lifecycle automation cuts the dead-account problem to near-zero.
• Decision trail for the next renewal. The trial data becomes the renewal scorecard, not a cold start.