Hello,You can use Multicharts to build an algo, and in fact, we at Optimus Futures think it's one of the better software to build an algo and trade on it because it's stability in execution. But, HFT would require you to host it and get an API that is compatible with such low latency execution. You can also consider working directly with an API if you are a programmer. We have experience with numerous API and deployed CTS-T4 and Rithmic.
Do you have algo traders at Optimus Futures that run their algos with NinjaTrader?