An API penetration test focuses on identifying security vulnerabilities within an application programming interface (API), which acts as a communication bridge between systems. It simulates attacks targeting authentication, authorization, data validation, and rate limiting mechanisms to uncover weaknesses like injection flaws, broken object level authorization, and excessive data exposure. The goal is to provide a detailed report outlining identified vulnerabilities, their potential impact, and actionable recommendations to improve the API's security posture and protect sensitive data exchanged through it.