A CAT (Computer-Assisted Translation) tools developer creates and enhances software applications that aid in the translation process. They design algorithms to facilitate machine translation, terminology management, and multilingual document management. They also ensure the software's compatibility with different operating systems and data formats. Their work involves debugging, troubleshooting, and improving the software based on user feedback. They also collaborate with linguists and translators to understand their needs and incorporate those into the software. Moreover, they continuously update the software to keep up with evolving language patterns and translation methodologies.