I wrote a bot to do this a few years ago. It would grab the order books from a set of exchanges and execute on the overlap. It had support for maker/taker fees

I wrote a bot to do this a few years ago. It would grab the order books from a set of exchanges and execute on the overlap. It had support for maker/taker fees as well as deposit/withdrawal fees for rebalancing accounts. I avoided USD trades as it required so much time to transfer. It worked well and it was a fun project to learn how markets functioned. The risk of missing the trade and the risk of hacks ultimately caused me to stop the experiment I had BTC in bter when it was hacked. That more than wiped out all of the profits I had made arbitraging.