This API client security vulnerability highlights the importance of thorough testing and validation. Popular API clients like Postman and Insomnia employ custom JavaScript sandboxing to restrict access to privileged parts of their applications, but these sandboxes are not foolproof. By leveraging Electron's built-in browser and Node.js integration, these tools provide a user-friendly GUI for testing and debugging APIs. However, scripting capabilities within these tools pose a security risk if not implemented correctly, allowing attackers to exploit vulnerabilities such as arbitrary code execution or access to sensitive system resources. To mitigate this risk, developers must be aware of the threat model of their chosen API clients and take steps to implement robust JavaScript sandboxing using available tools. The case studies of Insomnia and Postman demonstrate the importance of security in developer tools and provide guidance on implementing secure sandboxing approaches. By understanding these vulnerabilities and implementing effective countermeasures, developers can protect themselves against potential attacks and ensure a safer online experience.