A Blackbox Testing developer conducts tests on software applications without having knowledge about the internal workings of the system. They focus on the input that goes into the software and the output it produces, without concerning themselves with how the output was produced. They design test cases based on the software requirements and specifications, ensuring the software behaves as expected under various scenarios. Their goal is to identify any errors, bugs, or discrepancies in the software's performance. They also ensure that the software is user-friendly, secure, and meets all its functional requirements.