A GreenSock developer specializes in using the GreenSock Animation Platform (GSAP), a suite of tools for scripted, high-performance animations in all major browsers. They work on creating interactive animations for websites, games, and applications. Their job involves scripting complex animation sequences, coordinating multiple animations, and manipulating SVGs and DOM elements. They are also responsible for ensuring the animations are smooth, efficient, and compatible across different devices and browsers. Besides, they often collaborate with designers and other developers, translating visual concepts into functional, engaging web experiences. They may also optimize and troubleshoot animation performance issues.