mKCP is a transport built into V2Ray from early on, sharing an instinct with Hysteria2: run over UDP and fight packet loss aggressively.

How it grabs speed

TCP backs off and slows on loss; mKCP does the opposite — it actively and redundantly resends packets, accepting retransmission overhead to deliver data fast. On badly lossy cross-border links, this speeds things up noticeably.

SponsoredWhere does the subscription link come from?Our partner provider gives you 1 GB of high-speed Hong Kong data at signup — import it in one click.Get high-speed nodes

The cost is blunt

To fight loss, mKCP sends a lot of redundant traffic — real data usage can be two to three times the payload. Be careful on metered VPSes or capped provider plans.

Where it stands today

mKCP is effective but crude and dated. For lossy scenarios more people now pick Hysteria2, whose congestion control is smarter and lighter on data. mKCP remains a fallback, especially when self-hosting with unmetered traffic.

mKCP offers header camouflage types (none, srtp, utp, wechat-video) that disguise UDP as video calls and the like. The camouflage type must match on both ends.