An ETL (extract, transform, load) developer is an information technology specialist whose area of expertise is data warehouse solutions. As an ETL developer, your responsibilities include overseeing the big picture data warehousing needs of your company. You work with a team of IT professionals to assess current data storage systems, evaluate needs, and determine the best way to meet those requirements. Once you have developed the new data warehouse system, you oversee the extraction of data from other sources, the uploading of that data into the new system, and testing and troubleshooting to ensure everything works properly.