An AppScan Source developer specializes in using IBM's AppScan Source software to identify, fix, and prevent security vulnerabilities in web applications. They assess and interpret the vulnerability data generated by the tool, ensuring the application code is secure from potential threats. They also customize the software to meet specific needs, create detailed reports of the application's security status, and provide guidelines for remediation. Additionally, they are responsible for integrating AppScan into the development process to promote a proactive approach to application security. Their overall goal is to maintain the safety and integrity of web applications.