The Required API Security Checklist [XLS download]

APIs are the foundation of modern applications — and attackers know it. A single exposed token, misconfigured endpoint, or forgotten API can give cybercriminals direct access to your systems and sensitive data. With APIs expanding faster than security teams can monitor, API security has become one of the most urgent priorities of 2025.

In 2024, over 439 AI-related CVEs were reported — a 1,025% increase from the year before — and almost all were tied to insecure APIs. More than half of organizations faced an API-related incident in the past 12 months. Clearly, API security isn’t optional; it’s essential.

What Is an API Security Checklist?

An API security checklist is a structured, repeatable guide that ensures your teams never miss critical security controls. Much like a pilot’s pre-flight checklist, it helps security and engineering teams enforce the same protective measures across every API — from design and development to deployment and monitoring.

The goal? Reduce API risk, strengthen governance, and make security consistent and repeatable. This checklist becomes even more important with the rise of non-human identities (NHIs) — machine accounts, bots, and service credentials that often operate without proper oversight.

Why Every Organization Needs an API Security Checklist

1. Reduces Cyber Risk

Every week, another company faces an API breach. A structured checklist transforms API security from guesswork into a repeatable, automated process that lowers your attack surface and prevents common misconfigurations.

1. Enforces Zero Trust

A checklist helps operationalize the Zero Trust model, where every request — human or machine — is verified and authorized. It enforces least privilege, scoped tokens, and time-bound permissions to ensure no API call has more access than it needs.

1. Improves Visibility and Accountability

APIs often lack ownership. A checklist ensures monitoring, logging, and auditing are built in — so you always know who accessed what, when, and why.

1. Strengthens Compliance

Frameworks like SOC 2, GDPR, HIPAA, and ISO 27001 require strict access controls and auditability. Embedding a checklist ensures compliance is not a one-time task but an ongoing part of your operations.

1. Promotes Consistency Across Teams

Large organizations often build APIs in silos. A company-wide checklist enforces consistency between DevOps, platform, and security teams, ensuring the same standards everywhere.

4 Common API Risks You Can Overcome

1. Excessive Permissions

Over-scoped API keys or service accounts can expose entire systems. In one major breach, a single over-privileged key compromised 17 SaaS providers. A checklist ensures least privilege is enforced.

1. Weak Authentication

Many breaches stem from insecure authentication. APIs that lack proper login or token validation can expose sensitive data instantly. Strong authentication is non-negotiable.

1. Exposed or Hard-Coded Secrets

Developers still commit secrets to public repositories. Leaked API keys give attackers instant access to private environments. Secret management and automatic rotation must be standard practice.

1. Shadow or Misconfigured APIs

Untracked or forgotten APIs become open doors for attackers. An inventory and monitoring process keeps all APIs visible, secured, and compliant.

The Essential API Security Checklist

1. Strong Authentication and Authorization

Verify every request and enforce least privilege. Require multi-factor authentication, role-based access control, and short-lived tokens for both users and services.

Checklist items:

Enforce RBAC or ABAC

Require mTLS or signed requests

Replace standing privileges with expiring ones

Deny by default

1. Secure Non-Human Identities (NHIs)

Treat machine accounts and bots like any user — with ownership, visibility, and control. Enforce short-lived credentials and JIT (Just-In-Time) access.

Checklist items:

Inventory all NHIs

Assign owners and purposes

Rotate credentials automatically

Review access regularly

1. Secrets Management and Rotation

Never hard-code secrets. Use a central secrets manager to store credentials, inject them securely, and rotate them frequently.

Checklist items:

Store in a vault, not code

Scan for secrets in commits

Automate key rotation

Enable CI/CD secret scanning

1. Abuse Prevention and Rate Limiting

Stop brute-force and injection attacks with strict rate limits, schema validation, and behavioral monitoring.

Checklist items:

Enforce quotas and throttling

Add WAF/API firewall rules

Validate inputs and block mass assignment

Monitor abnormal traffic patterns

1. Logging, Monitoring, and Auditing

Maintain full traceability. Centralized, immutable logs are key to detecting and investigating attacks.

Checklist items:

Collect structured logs (JSON)

Track user/service identity, scope, and outcome

Send logs to SIEM/observability tools

Detect and block shadow APIs

1. Configuration Hardening

Secure the edge and mesh layers. Use TLS everywhere, enforce strict CORS policies, and set secure defaults.

Checklist items:

TLS 1.2+ only

Deny by default routing

Enforce gateway authentication policies

Apply WAF and request size limits

1. Incident Response and Recovery

Prepare and rehearse your API breach response plan. Quick action limits damage.

Checklist items:

Maintain “kill switch” for keys/tokens

Revoke credentials instantly

Preserve logs for forensics

Practice response drills

1. Third-Party API Security

Treat external APIs as untrusted. Limit partner credentials and validate every response.

Checklist items:

Use allowlists for egress traffic

Validate and sanitize responses

Assign minimal scopes per partner

Rotate partner credentials

1. API Inventory and Classification

Know your APIs. Track every internal, external, and partner API, and classify by sensitivity.

Checklist items:

Automate API discovery

Tag by data type and environment

Assign owners

Update inventory continuously

1. Secure Design and Data Minimization

Build secure-by-design APIs. Only expose what’s necessary, and validate all data exchanged.

Checklist items:

Enforce schema validation

Mask or tokenize sensitive fields

Reject unexpected fields

Return minimal data

1. Continuous Security Testing

Integrate testing into the SDLC, not just production. Run SAST, DAST, and fuzzing regularly.

Checklist items:

Embed testing in CI/CD

Scan for leaked secrets

Pen test after major changes

Automate re-testing

1. Data Encryption

Encrypt in transit and at rest. Use strong cryptography and manage keys securely.

Checklist items:

TLS 1.2+ for all traffic

AES-256 for data at rest

Rotate keys regularly

Limit key access

1. Governance of Machine Identities

Every token, bot, and service account should have an owner, scope, and lifecycle.
Checklist items:

Define NHI lifecycle

Automate reviews

Apply Zero Trust

Log all NHI actions

1. Compliance and Access Reviews

Schedule regular access reviews and align with compliance standards like SOC 2, HIPAA, and GDPR.

Checklist items:

Run periodic access certifications

Map API access to compliance controls

Document audit findings

Remediate access drift

1. Developer Training and Secure Defaults

Security must be built in, not added later. Train developers and provide secure-by-default templates.

Checklist items:

Offer secure SDKs

Run security workshops

Integrate scanning tools

Enforce default secure configs

1. Runtime Protection and Continuous Improvement

Treat this checklist as living. Review it, improve it, and adapt it to new API threats.

Checklist items:

Run red-team API simulations

Monitor for anomalies

Update checklist regularly

Integrate threat intelligence

Turning the Checklist Into Action

A robust API security checklist turns chaos into control. It brings structure, repeatability, and automation to your API defense strategy — ensuring every API, every token, and every identity is accounted for.

By automating least privilege, JIT access, and auditable workflows, platforms like Apono make it easier to secure APIs without slowing down innovation.

In 2025, API security isn’t just about protection — it’s about visibility, control, and trust. Make your checklist your blueprint for safer, smarter APIs.