ATLAS coding developers work on the ATLAS experiment at CERN, a particle physics project. They develop, implement, and maintain software that's used in data analysis, simulation, and processing. This involves writing algorithms for detecting and measuring particles, improving data quality, and optimizing data storage. They also test and debug these software systems, ensuring they work efficiently and correctly. Their work aids physicists in interpreting the data from the ATLAS detector, contributing to our understanding of the fundamental forces and particles of the universe. They often collaborate with scientists, engineers, and other developers, requiring excellent teamwork and communication skills.