At the end of 2018 I noticed a big arbitradge margin across markets in the cryptocurrency world. Meaning, I could buy and sell the same cryptocurrency at different prices at different markets at the same time. Because of this, my brother and I started programming a software that could that advantage of this. For about a year, we learnt a lot, had fun and made a profit (while the margins lasted). On 2021 I published the code on Gitlab. Entire project is here.