An Apache ActiveMQ developer designs, implements, and maintains message-oriented middleware systems using the ActiveMQ platform. They are responsible for developing applications that enable asynchronous communication between different components of a software system. They work on creating robust, scalable, and secure messaging solutions for real-time data sharing. They also debug and resolve issues, ensuring optimal performance and system stability. Their job includes configuring and managing ActiveMQ brokers, creating message queues and topics, and integrating ActiveMQ with other technologies. They also work closely with other team members, sharing knowledge and contributing to architectural decisions.