nostr:nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpq59ypwap8a2vtt9732whltjlglsdwh085l8c6gq9k9c33ckdus4eq3w3q9y technically doesn't matter what language as long as you can send udp packets, but all of it other than needing an external server to know your public ip can be client side

nostr:nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpq59ypwap8a2vtt9732whltjlglsdwh085l8c6gq9k9c33ckdus4eq3w3q9y apparently google has a STUN server so you prob don't even need to code anything server side