To be fair, I didn't look very hard for a good platform. I was aware of a couple that I had heard about either through friends or tangentially through HN comments on other stories but when I looked into them they either looked super shady and untrustworthy (yeah, I know, judging the book by it's cover) or forced you to implement your strategy in their language of choice (one was Python, one was a proprietary script-y language) and I wasn't interested in that.
Surprisingly it wasn't as much work as you'd think. It started as a hobby on the side so I wasn't worried about building a full-fledged trading platform that supported every exchange and every imaginable strategy type so I was free to keep it simple and focus on the one exchange I had an account at (GDAX) and the two or three strategies I had in mind at the time.