Getting Started with Postman for API “Security” Testing: Part 1 Postman is a useful tool used by many developers to document, test and interact with Application Programming Interfaces (APIs). With the ubiquity of APIs in mobile, web and other applications, Postman can be a useful tool for a security tester or developer to evaluate the security posture of the API. Part 1 of this blog series is to provide the basics of using Postman, explaining the main components and features.