QUIC, or Quick UDP Internet Connection, is a multiplexing transport based on UDP, initially designed, implemented, and deployed by Google.

QUIC has the following advantages:

  1. Reduced number of roundtrips in handshake phase. (1-RTT or 0-RTT)
  2. Multiplexing without head of line blocking as in TCP
  3. Connection migration, especially for clients. For example, connections don't break when device moves from Wi-Fi to 4G.

QUIC is now an experiment in V2Ray. It implements IETF specification. As the spec is still being standardized, compatibility can't be guaranteed.

Update History

V2Ray 4.7:

  • Initial version to support QUIC.
  • Default settings:
    • 12 byte Connection ID
    • Connection timeout in 30 seconds if no data traffic. (May have impact on some long HTTP connections)


QUIC is used as quicSettings in transport settings. The configuration must be exactly the same between connecting peers.

QUIC requires TLS. If TLS is not enabled in transport settings, V2Ray will automatically issue a TLS certificate for it. When QUIC transport is used, encryption in VMess can be turned off.

  "security": "none",
  "key": "",
  "header": {
    "type": "none"

security: "none" | "aes-128-gcm" | "chacha20-poly1305"

Extra encryption over entire QUIC packet, include the frame head part. Default value is "none" for no encryption. After being encrypted, QUIC packets can't be sniff'ed.

key: string

Key for the encryption above. Can be any string. Only effective when security is not "none".

header: HeaderObject

Configuration for packet header obfuscation.


  "type": "none"

type: string

Type of obfuscation. Corresponding inbound and outbound proxy must have the same settings. Choices are:

  • "none": Default value. No obfuscation is used.
  • "srtp": Obfuscated as SRTP traffic. It may be recognized as video calls such as Facetime.
  • "utp": Obfuscated as uTP traffic. It may be recognized as Bittorrent traffic.
  • "wechat-video": Obfuscated to WeChat traffic.
  • "dtls": Obfuscated as DTLS 1.2 packets.
  • "wireguard": Obfuscated as WireGuard packets. (NOT true WireGuard protocol)

When neither encryption nor obfuscation is enabled, QUIC transport is compatible with other QUIC tools. However it is recommended to enable either or both for better undetectable communication.