Build vs. Buy for SAML SSO and SCIM Provisioning

SAML itself is a standard, but every identity provider implements it with its own quirks: different attribute naming conventions, different certificate rotation behaviors, different tolerance for clock skew between systems. A homemade integration tested against one identity provider, commonly whichever one the engineering team happens to use internally, often breaks in small, confusing ways against a customer's different provider, and each new provider your customers use can surface a fresh edge case.

SCIM automates account lifecycle: creating a user account when someone's added to an approved group in the customer's identity provider, updating attributes like their name or role when those change, and deactivating their account the moment they're removed, without anyone in your product needing to take a manual action. That last piece, timely deprovisioning, is often the specific feature a security-conscious enterprise customer cares about most, since a stale account for a departed employee is a real, named risk their own compliance team is required to track down and close.

A common mistake is scoping SCIM as a single build task: accept a create request, save the user, done. For example, the gaps appear later, when a customer changes a user's role, moves someone between groups, or removes them, and each event needs its own handling and its own test. A better approach is to list every lifecycle event a customer's identity team can trigger, such as create, update, group change and deactivate, then write one test per event before the first enterprise rollout. That list also gives your sales team an honest answer when a prospect asks exactly what your provisioning supports.

Certificate rotation is a common failure point: a customer's identity provider rotates its signing certificate on its own schedule, and if your integration doesn't handle that rotation gracefully, every login from that customer suddenly fails with no obvious cause from their side. Attribute mapping is another: a homemade integration hardcoded around the attribute names one provider uses will silently fail, or worse, provision accounts with missing or wrong data, against a provider that names the same concept differently. Both failure modes tend to surface weeks after launch, once a routine certificate rotation happens on its own schedule, not during initial testing when everything still looks correct.

A mature identity and access management platform has already absorbed the accumulated edge cases across dozens of real identity providers, handles certificate rotation and clock skew tolerance correctly by default, and gives you a single, consistent integration point regardless of which specific provider a given customer uses on their end. The tradeoff is cost, usually a real per-connection or per-seat fee, weighed against the engineering time a homemade version would otherwise consume across every new provider quirk that surfaces after launch.

If you have exactly one or two enterprise customers and both happen to use the same, well-documented identity provider, a carefully built and thoroughly tested homemade integration can genuinely work and save real cost. The moment you're selling to enterprise customers broadly, where you don't control which identity provider a given prospect uses, the accumulated edge cases across providers tend to make a dedicated platform the faster and more reliable path, and the sales cycle rarely allows time to debug a new provider's quirks live during a customer's own rollout.

A dedicated identity platform usually wins when several of these are true:

• You sell to enterprise customers broadly and don't control which identity provider a given prospect uses.
• Your sales cycle leaves no time to debug a new provider's quirks live during a customer's own rollout.
• Certificate rotation and clock skew tolerance would otherwise be your team's job to handle correctly for every provider.
• Attribute names differ across providers, and hardcoded mappings would silently provision accounts with missing or wrong data.
• Customers' security teams will audit for stale accounts, so deprovisioning must be tested end to end, not only account creation.

Say a homemade SCIM integration correctly creates new accounts when employees join a customer's team but was never actually tested for the deactivation event, since that path is harder to trigger in a demo environment. Months later, the customer's security team runs a routine access review, finds several accounts for employees who left the company months earlier still active in your product, and flags it as a real finding in their own audit. The creation half of SCIM worked. The deprovisioning half, the part that mattered most to their actual security posture, was the part nobody had tested end to end.