A Google Hangouts developer designs, develops, and maintains applications for Google Hangouts, a communication platform that includes instant messaging, video chat, SMS, and VOIP features. They work with Google's APIs and SDKs to integrate Hangouts with other services or to create new features. Their tasks involve coding, debugging, testing, and troubleshooting to ensure optimal functionality. They also collaborate with other developers, UX designers, and product managers to improve user experience, implement new updates, and fix any technical issues. Their goal is to enhance communication and collaboration through the Hangouts platform.