What are the APIs that can be used on Linux ? Ideally it should be a C/C++ one but Java or .Net are ok as long as they can be used on Linux. I found so far the following established APIs: 1. Rithmic Pros: seems fast, seems to have a C++ version. Reasonable price. Cons: it's very difficult to get hold of it. 2. CQG Pros: seems fast. Cons: seems to be native Windows (it's not clear if it can be used on Linux). Getting it seems easier than Rithmic but they still make you go through hoops. Also, the price for using it is unclear. 3. CTS T4 Pros: seems reasonably fast, seems very easy to get hold of : the documentation is online, and they offer a demo. Reasonable price. Cons: it is .Net native, it's not at all clear if it can be used on Linux. For me, Rithmic would be ideal, however if I cannot get it in a reasonable time, I'll go to another solution. Are there other APIs in the vicinity of $100/month that can be used on Linux ?