They should centralise identity policy and make each API enforce the same authorisation model rather than letting applications invent their own rules. The practical goal is consistent claims, narrow scopes, and visible revocation across the estate. Without that, teams create local exceptions that are hard to audit and harder to remove.
Why This Matters for Security Teams
Governance across many APIs is not just an integration problem. It is an identity problem, because every API becomes a policy enforcement point for non-human identities, service accounts, tokens, and machine-to-machine calls. When teams let each application define its own scopes, claims, or approval logic, access sprawl follows quickly. NHI Mgmt Group research shows that 97% of NHIs carry excessive privileges, which is why API governance must focus on shared policy, not local convenience. See the Ultimate Guide to NHIs and the OWASP Non-Human Identity Top 10 for the broader risk context.
For digital transformation programmes, the practical issue is consistency. If one API accepts broad static keys, another relies on ad hoc JWT claims, and a third uses custom allowlists, revocation becomes uneven and audit evidence fragments. Mature programmes instead standardise on a single identity model, a small number of scope patterns, and central policy decision points. That lets security teams see what is allowed, where it is allowed, and how quickly it can be removed when a workload changes.
In practice, many security teams encounter privilege creep only after an API key has already been reused across multiple systems and the original owning team has moved on.
How It Works in Practice
The cleanest pattern is to treat APIs as governed resources rather than isolated products. Central identity policy defines which NHI or workload identity may call which API, under what conditions, and with what claims. Each API then enforces the same model at the edge, often through an API gateway, policy engine, or service mesh. Current guidance suggests using short-lived, narrowly scoped credentials and explicit revocation paths rather than long-lived shared secrets. NHI Mgmt Group guidance in the Ultimate Guide to NHIs — Lifecycle Processes for Managing NHIs is especially relevant here, and the Top 10 NHI Issues explains why unmanaged secrets and access sprawl persist.
- Use one authoritative identity source for API clients, not per-application exceptions.
- Prefer workload identity and signed tokens over static API keys where the platform supports it.
- Map every API operation to a small set of claims or scopes that are reusable across teams.
- Evaluate policy at request time so revocation takes effect immediately, not at the next deployment.
- Separate human approval workflows from machine runtime access, so emergency changes do not become permanent.
For implementation alignment, the NIST Cybersecurity Framework 2.0 is useful for governance and access discipline, while the NIST Cybersecurity Framework 2.0 and the OWASP Non-Human Identity Top 10 both support least privilege, verification, and lifecycle control. The strongest programmes also tie API access to lifecycle events such as onboarding, rotation, and offboarding so dormant entitlements do not survive organisational change. These controls tend to break down when legacy APIs cannot validate modern tokens because teams fall back to shared credentials and side-channel exceptions.
Common Variations and Edge Cases
Tighter API governance often increases operational overhead, so organisations have to balance developer speed against control consistency. That tradeoff is real, especially during mergers, cloud migration, or platform modernisation, when many APIs are owned by different teams and were built with different identity assumptions. Best practice is evolving here, and there is no universal standard for every API style, but the direction is clear: move away from bespoke local rules and toward centrally defined policy with local enforcement.
Some APIs will not support rich claims or fine-grained scopes, so the control model may need a gateway, broker, or translation layer. Others will rely on multiple identity types, including internal workloads, partner integrations, and third-party automation. In those cases, policy should distinguish between trust tiers rather than treating every client the same. The 52 NHI Breaches Analysis shows how quickly weak service-account discipline becomes a wider compromise path, and the Ultimate Guide to NHIs — Regulatory and Audit Perspectives is useful when access rules need to stand up to review.
Where environments include third-party developers or external API consumers, organisations often need stronger segmentation, tighter scope design, and more aggressive token lifetimes. The real test is whether access can be revoked everywhere without waiting for code changes, redeployments, or manual cleanup in multiple product teams.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST CSF 2.0 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 | Centralised scopes and claims reduce API identity sprawl. |
| NIST CSF 2.0 | PR.AC-4 | Addresses access management for machine identities across services. |
| NIST Zero Trust (SP 800-207) | SC-4 | Supports continuous verification and policy enforcement at request time. |
Standardise workload identities and scope design across APIs, then reject local auth exceptions.
