I wrote a bot but could never make money due to the transaction fees. I wanted to make 15-20 trades per day. Instead, had to limit it to 3 or 4, meaning a lot more burden on each trade to be right.

The funnest part of writing a bot is using all the historical data to observe how the bot would have done during that period. I ended up checking thousands of permutations of parameters by brute force to determine the best ones, but in the end transaction fees killed me. I didn't have the confidence to do it at a large enough scale to make money I guess.