Dropping messages occasionally can be fine, but the problem with UDP is that the packet loss is silent. I believe UDP can be lossy even on localhost when there

Dropping messages occasionally can be fine, but the problem with UDP is that the packet loss is silent. I believe UDP can be lossy even on localhost when there's technically no network, so you'd have to track the message count on both the sender and recipient sides. It's also more sensitive to minor glitches, whereas TCP + a very small buffer would allow you to smooth over those cases. I use NATS (which is UDP-based) for a similar kind of firehose system, and the amount of loss can sometimes reach 6-7%.