Name three real systems that use UDP and why.

UDP in production

For Name three real systems that use UDP and why., interviewers listen for a crisp definition, how the pieces interact in a real system, and one trade-off or failure mode you have seen or would guard against.

• DNS — small query/response, loss = retry at app layer.
• VoIP / gaming — tolerate loss; latency matters more than retransmit.
• Metrics (StatsD) — fire-and-forget telemetry.