API security best practices are really NHI governance problems

At a glance

What this is: This is StrongDM’s overview of 13 API security practices, with a strong emphasis on authentication, least privilege, logging, and third-party control.

Why it matters: It matters to IAM and NHI practitioners because APIs routinely depend on non-human identities, so weak API controls become weak identity controls.

By the numbers:

• 97% of NHIs carry excessive privileges, increasing unauthorised access and broadening the attack surface.
• 79% of organisations have experienced secrets leaks, with 77% of these incidents resulting in tangible damage.

👉 Read StrongDM's guide to 13 API security best practices for 2026

Context

APIs are the operational layer where applications, services, and automated workflows exchange data, but they also concentrate credentials, permissions, and trust assumptions. In practice, that makes API security a non-human identity problem as much as an application security problem, because service accounts, tokens, and machine clients often drive the access path.

The source article treats API protection as a checklist of controls, but the deeper issue is governance: organisations still assume API access is easier to contain than human access. That assumption breaks down when APIs are embedded across cloud, CI/CD, and third-party integrations, which is why NHI visibility, rotation, and least privilege matter here. For a deeper NHI control baseline, the Ultimate Guide to NHIs is the right reference point.

Key questions

Q: How should security teams govern API access for non-human identities?

A: Security teams should govern API access by treating every key, token, certificate, and service account as a managed identity with ownership, expiry, scope, and revocation rules. The right model combines least privilege, continuous logging, and scheduled rotation so access is usable for the task but not durable beyond it.

Q: What is the difference between API security and NHI governance?

A: API security focuses on protecting endpoints, traffic, and application behavior. NHI governance focuses on the identities that use those APIs, including service accounts, tokens, and certificates. In practice, the two overlap because weak machine identity controls become weak API security, especially when privileges and credentials are not lifecycle-managed.

Q: When does API access become a high-risk identity problem?

A: API access becomes high-risk when credentials are long-lived, broadly scoped, poorly logged, or reused across environments. Risk also rises when third-party integrations can call sensitive systems without clear ownership or periodic review. At that point, the problem is no longer only application security, it is unmanaged machine identity.

Q: Why do least privilege and logging both matter for API governance?

A: Least privilege limits what an API identity can do, while logging shows what it actually did. You need both because restrictive permissions reduce blast radius and audit data reveals misuse, drift, or compromise. Without logging, identity review is incomplete; without least privilege, logs only document excessive access after the fact.

Technical breakdown

How API authentication becomes NHI trust

API authentication is usually built around tokens, keys, certificates, or federated identity assertions rather than interactive logins. That shifts the security problem from user sign-in to machine trust: if a token is stolen, replayed, or never expires, the API will often accept it exactly as designed. MFA helps only at the point of issuance or administrative access, not at every downstream call. In NHI environments, the main risk is not just credential theft but credential persistence and unchecked reuse across systems.

Practical implication: Treat API authentication artifacts as governed identities with lifecycle controls, not as static integration settings.

Least privilege, RBAC, and ABAC in API control

API access control is most effective when permission is scoped to the narrowest feasible action, resource, and context. RBAC works when roles are stable and simple, while ABAC is better when access depends on attributes such as workload, environment, time, or data sensitivity. For APIs, the challenge is that broad scopes are often granted for developer convenience and then left in place. That creates hidden standing privilege across services, automation pipelines, and vendor integrations.

Practical implication: Map every API scope to a named business function and review whether the scope still matches the workload that uses it.

Logging, rate limits, and lifecycle management for APIs

Logging and throttling are not just availability controls. In API environments they also provide evidence, anomaly detection, and a way to constrain abuse when credentials are compromised. Lifecycle management matters because APIs, like NHIs, can remain active long after the team that created them has moved on. When retirement, rotation, and revocation are inconsistent, the control gap becomes structural rather than incidental. That is where many organisations lose sight of who can still call what.

Practical implication: Require a decommissioning path for every API, including revocation of credentials and removal of unused integrations.

Threat narrative

Attacker objective: The objective is to turn trusted machine access into quiet, repeatable control over data and workflows.

1. Entry occurs when attackers obtain an exposed API key, over-permissioned token, or compromised third-party integration.
2. Escalation follows when the same identity can call broader endpoints, enumerate data, or reach privileged administrative functions.
3. Impact occurs when the attacker uses legitimate API access to exfiltrate data, alter records, or automate fraudulent actions at scale.

Breaches seen in the wild

• Shai Hulud npm malware campaign — Shai Hulud campaign: npm malware exposed secrets on GitHub.
• Salesloft OAuth token breach — hackers stole OAuth tokens to access Salesforce data via Salesloft.

Read our 52 NHI Breaches Analysis report for a comprehensive view of breaches impacting Non-Human Identities including AI Agents.

NHI Mgmt Group analysis

API security is now an NHI governance problem, not only an application hardening problem. APIs are increasingly consumed by service accounts, automation, and agentic workflows, which means the identity layer determines the real control boundary. Organisations that treat API keys as mere configuration objects miss the lifecycle, ownership, and offboarding issues that make machine access durable. The practical conclusion is that API security and NHI governance should be managed through the same operating model.

Least privilege is only meaningful when entitlement sprawl is measured at the identity level. API guidance often recommends RBAC, ABAC, and rate limits, but those controls fail when the underlying identity can still reach far more than the task requires. The underlying pattern is privilege accumulation across integrations, not just overbroad code permissions. The practical conclusion is to enforce entitlement reviews on machine identities with the same discipline used for human access.

Runtime visibility is the missing control in most API programmes. Many organisations can describe what an API should do, but cannot reliably show what it actually does after deployment, especially across third-party dependencies. That is why monitoring, auditability, and revocation need to be designed as governance controls, not after-the-fact detective measures. The practical conclusion is to require continuous evidence for every API-connected identity.

Ephemeral access only reduces risk when the surrounding trust model is also ephemeral. Time-limited credentials help, but they do not solve the deeper problem if the service account, integration, or downstream authorization remains broadly trusted. This is the named concept worth carrying forward: ephemeral credential trust debt: short-lived access that still inherits long-lived assumptions about scope, reuse, and oversight. The practical conclusion is to pair short credential lifetimes with strong ownership and revocation discipline.

Third-party API access should be treated as supply chain access. API integrations often extend trust beyond direct employees into vendors, SaaS apps, and embedded workflows, which makes visibility and assurance essential. A control set that ignores connected third parties will miss the most likely route to lateral access. The practical conclusion is to inventory external integrations as part of identity risk management, not as a separate application exercise.

From our research:

• 79% of organisations have experienced secrets leaks, with 77% of these incidents resulting in tangible damage, according to the Ultimate Guide to NHIs.
• 96% of organisations store secrets outside of secrets managers in vulnerable locations including code, config files, and CI/CD tools.
• For the control path forward: use the 52 NHI Breaches Analysis to map recurring failure modes to compensating controls.

What this signals

Ephemeral credentials do not eliminate governance debt. They shorten exposure windows, but they still depend on ownership, scope control, and revocation discipline. For teams that already struggle with unmanaged service accounts, the real signal is that short-lived access only works when the identity lifecycle is already under control.

With 1.5 out of 10 organisations highly confident in securing NHIs, the operational gap is not theoretical, it is a maturity problem that will surface first in machine-to-machine pathways. API programmes should therefore be planned as identity programmes, with explicit accountability for every non-human credential that can reach production.

The next step for most teams is to connect API access policy to inventory, rotation, and third-party review. That means aligning internal control design with the OWASP Non-Human Identity Top 10 so that API governance is evaluated against the same risk patterns that attackers actually exploit.

For practitioners

• Inventory API-connected non-human identities Catalog every API key, token, certificate, service account, and automation identity that can call production endpoints. Include ownership, expiry, scope, and the systems each identity can reach.
• Shrink privileges to task-scoped access Replace broad API permissions with narrow scopes mapped to specific workflows, environments, and data classes. Reassess dormant integrations and remove permissions that are not required for current operations.
• Enforce rotation and revocation on a schedule Set rotation requirements for all API credentials and tie revocation to offboarding, change management, and incident response. Do not leave long-lived tokens embedded in code, pipelines, or documentation.
• Centralise logging for API calls and identity actions Correlate API request logs, identity events, and privilege changes so responders can see who or what called which endpoint, from where, and under what authority.
• Review third-party integrations as trust extensions Revalidate OAuth apps, vendor integrations, and partner APIs before they are allowed to touch sensitive environments. Require explicit approval for any integration that expands access to regulated or high-value data.

Key takeaways

• API security fails fastest when machine identities are treated as configuration rather than governed identities.
• The largest practical risk is credential sprawl combined with broad access, not API traffic volume alone.
• Teams should align API controls with NHI lifecycle management, or they will keep detecting the same failures too late.

Key terms

• Non-Human Identity: A non-human identity is any machine credential used by software, services, or automation to authenticate and access resources. It includes service accounts, API keys, tokens, certificates, and AI agents. These identities need ownership, rotation, monitoring, and revocation just like human accounts, often with tighter controls because they operate at scale.
• Ephemeral Credential: An ephemeral credential is a short-lived secret or token issued for a limited task or time window. It reduces exposure if stolen, but it only lowers risk when scope, renewal, and revocation are tightly governed. Short duration alone does not make access safe if the underlying identity remains over-privileged or poorly monitored.
• Least Privilege: Least privilege is the principle of granting only the minimum access needed for a specific task. In NHI environments, it should be applied to identities, scopes, endpoints, and data paths, not just to users. The control is effective only when permissions are reviewed and reduced as workflows change.
• API Lifecycle Management: API lifecycle management is the practice of governing APIs from creation through versioning, change, retirement, and revocation. For security teams, the important part is tying identity controls to each phase so credentials, permissions, and integrations do not outlive the service they support. That keeps machine access from becoming permanent by default.

Deepen your knowledge

API authentication, least privilege, and lifecycle controls are core topics in our NHI Foundation Level course, the industry's only accredited NHI security programme. If your team is already responsible for API access, it is worth exploring.

This post draws on content published by StrongDM: 13 API Security Best Practices to Know in 2026. Read the original.