IBM's provided a free developer course, including a free z/OS account, for at least a decade now: https://www.ibm.com/z/resources/zxplore https://www.ibm.com/z/

IBM's provided a free developer course, including a free z/OS account, for at least a decade now: https://www.ibm.com/z/resources/zxplore https://www.ibm.com/z/resources/zxplore Going through the challenges is worth it just to see how the mainframe way of doing things works, even if you never plan to use a mainframe in your career. There's a lot of core concepts and cultural touchpoints that help you build more reliable systems everywhere else.