This platform is an alternative to HackTheBox. It has a very similar concept where it gives you a platform to safely and legally practice hacking into computer systems. It also has a lot of community support through tutorials and forums that provide guidance on how to approach each challenge.
Hackthebox is a great platform for getting practical pen testing experience in a competitive game like environment. This company provides you with several servers that you can connect too remotely with files containing certain codes. The challenge is to hack into the machine, retrieve the code and upload it in order to earn points and increase your ranking. They consistently add new boxes/challenges and there are plenty of online tutorials to help you learn as you go.
Linux Academy is one of the best platforms for learning programming and cloud technologies I’ve come across. They have prep courses on AWS certifications, google cloud, microsoft azure and they allow you to login to those platforms and get hands on experience using it. Additionally, they offer many programming courses, allow you to spin up your own virtual machine and practice in the environment of your choice to learn different operating systems. Lastly, they allow you to pick “learning paths” and direct you in learning the skills required to get into different areas of tech.
Codewars is an educational community for computer programming. On the platform, software developers train on programming challenges known as kata. They have several different challenges, offered in many different programming languages. After completing the challenges you will be able to see other users solutions and learn from other programmers in the community.
Topcoder itself is a crowdsourcing company that pays community members to work on projects and sells services to clients. It also has competitive programming competitions, which is a great way to practice your programming and improve by competing against other high quality programmers. I wouldn’t suggest this for beginners but more for intermediate level programmers looking to improve their skills.