API Business Logic Testing

Business logic vulnerabilities in APIs often involve race conditions in financial or inventory operations. Use ZAP's ability to send parallel requests to test race conditions. Common scenarios include double-spending, inventory manipulation, or coupon reuse. Configure multiple threads to send identical requests simultaneously, observing whether the API properly handles concurrent operations.

Workflow bypass testing examines whether APIs enforce proper state transitions. Many APIs implement complex workflows—order processing, approval chains, or multi-step transactions. Test by calling workflow steps out of order, skipping required steps, or manipulating state parameters. APIs might expose internal state management that web interfaces hide, creating unique bypass opportunities.