APIs are often a direct path to sensitive data and business functionality. I test API security controls to identify access-control, authentication, data-exposure, validation, and business-logic weaknesses.

Authentication — Test API authentication mechanisms, token handling, session controls, and common implementation weaknesses.

Authorization — Assess object-level and function-level access controls and whether users can access data or actions beyond their permissions.

Data exposure — Identify excessive data returned by endpoints, sensitive information exposure, and insecure API responses.

Input validation — Assess how endpoints handle unexpected, malformed, or attacker-controlled input.

Rate limiting & abuse controls — Review protections against excessive requests and relevant API abuse scenarios.

Business logic — Test important workflows for authorization gaps, parameter manipulation, and unintended functionality.

Scope & access → Endpoint discovery → Authentication review → Authorization testing → Input and business-logic testing → Evidence collection → Risk-based reporting → Retest where agreed.

The final report explains affected endpoints, security weaknesses, evidence, practical risk context, and remediation guidance so developers and security teams can act on the findings.

Share the API type, documentation or endpoint information, environment, and testing objective. I can help define the assessment scope.