Decent Broker For Sending Lotsa Quote

(apologies if I have cross posted.)

Looking for recs on what broker to use if I want:

- To post liquidity across 300+ names

- C, C++, Java or UDP (socket level) API

- Historical CQS/CTS, etc.

- Portfolio margin

Thanks!

 

sending orders using UDP? Whatcha talkin bout Zipf?

 

Traditionally MD feeds... but my point is that I don't mind whatever low-lat interface the broker exposes.