Should organisations buy an IAM provider or build identity features in-house for SaaS?

Why This Matters for Security Teams

For SaaS products, the buy-versus-build decision is really a question of where identity risk and operational burden should live. Buying an IAM provider usually accelerates federation, provisioning, audit trails, and policy enforcement, while building in-house can seem attractive for product differentiation. The catch is that identity features are not a one-time feature set. They require standards support, security hardening, tenant isolation, lifecycle workflows, and continuous compatibility work across customer environments. The control gap is especially visible in NHI programs, where Ultimate Guide to NHIs shows that NHIs outnumber human identities by 25x to 50x in modern enterprises.

That scale matters because SaaS identity is rarely limited to login screens. It extends to service accounts, API keys, SCIM provisioning, admin delegation, and audit evidence that customers will demand during procurement. Current guidance from NIST Cybersecurity Framework 2.0 favors repeatable governance, measurable access control, and continuous monitoring over bespoke identity logic that only one engineering team understands. In practice, many security teams discover the maintenance cost of homegrown identity only after enterprise sales cycles, incident response, or compliance reviews have already made it a production dependency.

How It Works in Practice

A practical SaaS approach usually starts by separating core product logic from identity plumbing. If the product needs SSO, SCIM, RBAC, audit logging, and session policy, buying a mature IAM provider is usually faster than implementing those controls yourself. A provider can also reduce the chance of subtle failures in token handling, lifecycle events, and tenant-specific authorization paths. For NHI-heavy services, that matters because leaked or stale secrets are common: Top 10 NHI Issues highlights how often secrets are stored outside proper controls, and the 52 NHI Breaches Analysis shows how identity mistakes become incident patterns, not isolated exceptions.

Where in-house building still makes sense is when identity behavior is central to the product. Even then, the safer pattern is to build only the product-specific decision layer and outsource commodity functions. That means using standards-based federation, short-lived tokens, and well-defined policy evaluation rather than inventing a proprietary auth stack. Common implementation choices include:

• Use external IdP integration for SSO and MFA instead of custom password stores.
• Prefer SCIM or equivalent provisioning standards over bespoke user sync logic.
• Keep authorization decisions policy-driven, with clear RBAC boundaries and auditable overrides.
• Log entitlement changes, token issuance, and admin actions as first-class security events.

This aligns with the operational model behind NIST CSF 2.0 and with identity-by-design principles in NIST Cybersecurity Framework 2.0, which treats access governance as a continuous control function rather than a feature sprint. These controls tend to break down when the product must support many enterprise tenants with conflicting identity policies, because bespoke exceptions quickly outgrow the original design.

Common Variations and Edge Cases

Tighter identity control often increases product complexity, so organisations have to balance speed against long-term ownership. That tradeoff is clearest in regulated SaaS, multi-tenant platforms, and products that expose admin APIs to customer automation. In those environments, a full build is rarely justified unless identity is itself the differentiated capability. Best practice is evolving, but there is no universal standard that says every identity touchpoint must be bought or built in the same way.

Hybrid models are common. A team might buy workforce federation and lifecycle management, then build product-specific authorization logic, delegated admin workflows, or customer-facing policy screens. That approach reduces reinvention while keeping control over the parts that affect the user experience. It also helps with breach resistance, because NHI failures often stem from weak lifecycle discipline rather than missing login features. For example, Snowflake breach and Salesloft OAuth token breach both reinforce how exposed credentials and weak governance can turn integration paths into attack paths.

The key exception is when a SaaS company is building identity infrastructure as its core product. In that case, building is the business. For everyone else, the safer decision is usually to buy the control plane, build only the product-specific policy layer, and keep the scope narrow enough that security and compliance teams can actually operate it over time.

Related resources from NHI Mgmt Group

• How should organisations decide whether to build or buy workload identity tooling?
• How can IAM teams reduce the blast radius of a compromised SaaS identity?
• How should organisations govern embedded AI features inside SaaS apps?
• When should organisations restrict AI features in SaaS?