A good QA Tester is able to adapt and become productive in a shorter time than average when they're faced with an unfamiliar environment or skill-set. They have a broad knowledge of systems, experience with issues and vulnerabilities in software, and must be skilled with technology. A QA Tester is a professional who tests the functionality and usability of new or existing software before it goes live to ensure it is bug-free. They work closely with developers, providing them feedback on what needs improvement in order to produce top-quality programs that meet customer expectations.