I have already been working on this for a few months and it just went live a few weeks ago - I wanted to make it a paid backtester but with the shutdown, I figured people would want different alternatives, so here it is. Completely free and offers many strategies for testing.
If there is enough demand, we can add a lot more stuff.
Happy to answer any questions.
This is just a very basic strategy backtester, there are plenty like it, you can find them if you Google "technical backtester" and some of the brokers (e.g. TD Ameritrade) even let you do such backtests in their platforms (e.g. Thinkscript, though that's a tad more Quantopian-like than this tool).
If you want a _real_ Quantopian alternative, look at QuantConnect [0]. Interestingly, it's .NET based and you can write C#, F#, Python or whatever you want.
And the trading engine is open-source [1] and you can run it yourself.
I know it's not Quantopian right now but quantopian also started with a simple backtester which they then expanded quite well. I figured if there's enough interest, I'll just add on top of that idea and create something similar where you can backtest both with code and with just the UI.
