I'm not sure, however Sterling seems well equipped to handle API. Traders from Echo used it. Bright uses Redi Plus, although that was some years back and I'm not sure if that's changed. I've used Sterling, GreyBox and DasPro and of the three platforms, Das was the most simple and easy to set up regarding hot keys. Again, I didn't use it for API so it didn't apply. Also, there were a few threads that spoke highly of Takion, so you may want to investigate that platform as well.
