Are you looking to trade yourself via an API?You should use the FIX API from IBKR instead of the REST API, for performance and latency reasons and also rent a server nearby. You might consider data feeds (iqfeed,dxfeed) for CME products or platforms like Rithmic which also offer order execution/management.
If you mean having someone manage your capital and trade using your API credentials, I would suggest to stay away . In my experience, only sketchy firms tend to use this method to avoid financial regulation.