I spent the last year building a programming challenges site targeted at intermediate/advanced programmers [1]. Challenges follow the "Build your own X" format, where you learn about a popular open source tool by building a small version yourself (popularized by this Github repo [2]).
The primary difference compared to other coding challenge websites like Codecademy, HackerRank, Exercism etc. is that we offer real-world programming challenges - no inverting binary trees here!
I've posted about this multiple times here before, but haven't managed to gather much interest. Trying out a text post this time instead of just submitting a link.
Any feedback is welcome! I'd love for more people to try this out, it's a _very_ effective form of learning.
[1]: https://codecrafters.io/challenges
[2]: https://github.com/danistefanovic/build-your-own-x