7 releases

2.1.3-beta Oct 5, 2022
2.1.1-beta Sep 7, 2022
2.0.2-beta Apr 4, 2022
2.0.1-beta2 Mar 18, 2022
1.6.0-alpha6 Jul 27, 2021

#1759 in Network programming

Download history 97/week @ 2024-02-11 13/week @ 2024-02-25 1/week @ 2024-03-10 252/week @ 2024-03-31

253 downloads per month

MIT license

484K SLoC

C 314K SLoC // 0.1% comments Perl 150K SLoC // 0.1% comments C++ 7.5K SLoC // 0.1% comments GNU Style Assembly 6K SLoC // 0.1% comments Bitbake 2.5K SLoC // 0.1% comments Rust 1.5K SLoC // 0.0% comments M4 1.5K SLoC // 0.0% comments Visual Studio Project 677 SLoC Prolog 643 SLoC Assembly 311 SLoC // 0.1% comments C# 108 SLoC // 0.1% comments Shell 35 SLoC // 0.3% comments NuGet Config 7 SLoC

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MsQuic is a Microsoft implementation of the IETF QUIC protocol. It is cross-platform, written in C and designed to be a general purpose QUIC library. MsQuic also has C++ API wrapper classes and exposes interop layers for both Rust and C#.

Protocol Features

QUIC has many benefits when compared to existing "TLS over TCP" scenarios:

  • All packets are encrypted and handshake is authenticated with TLS 1.3.
  • Parallel streams of (reliable and unreliable) application data.
  • Exchange application data in the first round trip (0-RTT).
  • Improved congestion control and loss recovery.
  • Survives a change in the clients IP address or port.
  • Stateless load balancing.
  • Easily extendable for new features and extensions.

Library Features

MsQuic has several features that differentiates it from other QUIC implementations:

  • Optimized for client and server.
  • Optimized for maximal throughput and minimal latency.
  • Asynchronous IO.
  • Receive side scaling (RSS) support.
  • UDP send and receive coalescing support.



For information on contributing, please see our contribution guidlines. Feel free to take a look at our Good First Issues list if you're looking for somewhere to start. If you'd just like to talk, come chat with us on Discord.