The thing that always bothered me about learning to code online: you solve an exercise, hit Run, a green check appears, and you have no idea what it actually checked. On a lot of platforms it compared your printed output to a stored string. So you can pass with a hardcoded answer, a lucky hack, or code that only works for the one example shown. You "finish the course" and still cannot write the thing.
I wanted the exact opposite. So I built IWTLP, and it is live on Product Hunt today.
What is different
On IWTLP, every exercise:
runs your real code on a real server-side runtime (Python, C++, C, Fortran, and now Julia),
