I used to write trading systems for Amibroker. This one signaled the 2009 march bull market in equities and oil. But it is a swing/longterm trading system. I was a daytrader so it is not really useful for that.
I was writing that script for Amibroker platform (https://www.amibroker.com) but I believe the market leader is probably something like MetaTrader (https://www.metatrader4.com). Also, for developers or software engineers familiar with Python, Quantopian might be something you'll enjoy using (https://www.quantopian.com).
PS: anyway, sorry for digressing away from the topic of the HN thread lol