Interesting that QuantConnect can offer hosting at $20 per algorithm per month. Quantopian said this wouldn't even come close:
Some people ventured estimates of the size of the personal trading business. We only have a few hundred people trading real money. If we started charging $20/month (suggested earlier in the thread), and every single person agreed to pay, it would only be a fraction of the total cost. I just shared a longer version of this answer here.
So why would QuantConnect be able to charge $20 per algorithm per month, but it was not viable on Quantopian? Is it explained by the fixed costs and the limited participation rate on Quantopian? Are we sure that the only way that QuantConnect makes a profit is by charging for hosting?
The reason I'm bringing this up is that retail trading costs seem to be hard to pin down, and it germane to the zipline-live effort. For example, for an individual to do algorithmic trading on a set of N U.S. stocks every M days with turnover X, with $Y of capital, there ought to be a going market rate (direct and indirect, e.g. slippage, etc.). It should be like looking up the cost of electricity (a weak analogy, I know, but you get my point...by the way, a Google search yields 12 cents per kilowatt-hour, which in the end, should be relevant to algo trading, since cloud computing is a commodity, and it is really just the cost of electricity to keep it all running). For institutional trading of gazillions of dollars, I trust that the powers-that-be have this all worked out, but since there isn't a coherent market on the retail side of algo trading, it isn't a commodity yet as it should be (i.e. retail traders are getting ripped off).
They do make available their source code, which you can host on your own with your own servers or one of the cloud servers.For someone versed in the tribulations of version changes, library compatibilities, etc,, it might be worth hosting your own.
Another important point. The paradigm should be more like firmware not software (think router firmware versus desktop pc OS, with automatic updates), perhaps with a mirrored test instance to confirm changes, leaving it up to the individual quant whether to update or not, and when (perhaps still providing an "auto update" option). Running an algo with real money on a platform that is in perpetual beta, with no control over the changes--not where zipline-live should land, should it be implemented as the backbone to a hosted trading system.