Hi, I would like to know apart from FXCM, Oanda, Dukascopy, IB markets and Tradeking that offer a free API? Ie, not subject to minimum volume in trading, or fees/commisions? It does not matter if it is in C#, RESTFUL services, Java, FIX, whatever.
Preferable not shady brokers, ie regulated by the FSA/NFA/regulatory body of a country and ECN brokers -or at least not Dealing Desk brokers-
Thanks!
Any broker that has support for Spotware’s cTrader/cAlgo trading platform will allow you to connect via FIX API, you’ll need to either use a 3rd party FIX engine or make your own. If you are a .NET, Java or C++ developer, then OnixS is something you might be interested in: Low latency FIX Engine for .NET / C#, C++, Java - FIX Protocol : OnixS.
Spotware also has its own open API called Spotware Connect, reference can be found here: https://connect.spotware.com/documentation/section/api-reference.
There are several brokers (well regulated, and ECN) that support Spotware’s products. Most of them welcome algorithmic traders.
If you need any help, feel free to ask. 
Thanks for your answer ClarkFX. I downloaded cAlgo from IC Markets and it seems that it is a framework built on top of C# to create trading scripts, but I didn’t find one thing that maybe you can guide me: how can I programatically login to an IC Markets account, I can do it from cAlgo but I would like to create a dll in cAlgo and call it from another program, like Zorro Trader. For that I need to login programatically from cAlgo.
As I said in my earlier post, you can login programmatically into your IC Markets account through one of two methods provided by Spotware: Spotware Connect or their new FIX engine. And I already included the documentation that Spotware has provided as a start.
I’m not sure what you mean by creating a DLL in cAlgo, and calling it from Zorro Trader. If you want to build a library, it’s the same process as any normal .NET library. As far as I know Zorro is based in C++, so you can call your library using any options you’re comfortable with in C++. I’m not sure what you’re trying to accomplish with that though. Seems like a lot of redundancy to bounce between multiple platforms. Perhaps I am misunderstanding what you’re trying to do.
Mithrandir7
I’m interested to know if you have had success with running systems via Zorro through to the cAlgo FIX API / Spotware Connect API?