A Flume developer specializes in designing, building, and maintaining systems using Apache Flume, a distributed service for collecting, aggregating, and moving large amounts of log data. Their work involves creating custom components such as sources, sinks, and channels to handle specific data flows. They also work on optimizing Flume's performance and reliability, ensuring data integrity during transfer, and integrating Flume with other systems like Hadoop or Spark. Dealing with data ingestion from various data producers into Hadoop-based storage, they are crucial in big data projects. They troubleshoot issues, give technical guidance, and ensure the scalability of solutions.