An Aspen HYSYS developer designs, develops, and maintains simulation software used for process optimization in industries like oil and gas. Their work involves understanding the needs of engineers and scientists, and translating those needs into software functionalities. They work on enhancing the existing features, fixing bugs, and integrating new technologies to improve the software's performance. They also provide technical support, helping users troubleshoot any issues they encounter. Additionally, they collaborate with other team members, including project managers and testers, to ensure the software meets quality standards and user requirements. The developer uses coding languages like C++, C#, and Python.