Make my own little FCC

Is there a way to use the FCC platform to make my own challenges?

Is the FCC 'compiler an open source? can I use it to build a small ‘my-FCC’ site to practice html and JavaScript? ’

Absolutely. As long as you follow our BSD-3 license, you’re free to do whatever you want with the code. The simplest way to get started would be to get freeCodeCamp running locally, then start changing files in the /seed/challenges directory.