An Async developer designs and implements software applications using asynchronous programming. They develop systems that can perform multiple operations concurrently, improving efficiency and performance. They write code that initiates operations and then moves on to the next task before the first operation finishes, thus not blocking or waiting for the completion of the task. These developers often work with languages that support async programming such as JavaScript, Python, or C#. They handle tasks like API calls, database transactions, and other operations that could potentially block the execution flow, ensuring smooth, responsive, and efficient software applications.