Most exchanges support real-time Websocket and some even FIX protocol. Even HTTP-only for order entry is doable with advanced HTTP client frameworks (I use Akka-http).
HFT is when you are faster than most other traders. ;)
HFT is when you are faster than most other traders. ;)
Liked how you pattern match directly on JSON messages, I should di it more. :)
There are institutional-grade solutions (cross-connect, colocation in NY4, FIX feeds / order placement), available e.g. from Gemini (https://gemini.com), however, I am not sure that current overall Bitcoin trading volume is enough to warrant this. Both one-time setup and monthly fees for direct links are significant.