I'm a big fan of QuantConnect.

Previous to this, I was writing a code (mostly using AI) that would talk to IBKR directly.

Suffice to say, my code was pretty buggy, and I'd run into really strange things with interactive.

Also, I had to write my code twice:
1. Once for backtests
2. And a second time for live execution

And so naturally bugs cropped up between them.

I also always had to write code that would deal with fees and I was also paying Polygon $100/month for just data.

Being able to unify the code and backtest and run with the same code was a huge win for me. I actually saved money because I could cancel Polygon and just use their data.

QuantConnect does have some sharp edges. And some of the documentation and AI features took me a while to find out or to figure out. But it's certainly been worth it.

Also Jared, who is I believe the founder of the CEO at least is involved in the day-to-day operations. The Discord chat is really useful and really active, so you can always pop in and ask questions there. Their new AI bot in Discord ("Mia") has been super duper helpful. I'll often produce code samples directly from it - and often it "just works" right out of the box, so they're much better than using ChatGPT or Claude to generate code. The custom AI bot has better training data, so the code that it spits out is really good.

If you're at all on the fence on this, I would definitely try it out. It's definitely worth using it and has saved me so much time, frustration, and money. I'm a big fan.