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.

Documentation

• For platform support details, see the Platforms docs.
• For release details, see the Release docs.
• For performance data, see the Performance dashboard.
• For building the library, see the Build docs.
• For testing the library, see the Testing docs.
• For using the API, see the API docs or the Sample.
• For running a sample server and client app, see the Quick Start Guide.
• For deploying QUIC, see the Deployment docs.
• For diagnosing issues, see the Diagnostics docs and the Trouble Shooting Guide.
• For other frequently asked questions, see the FAQs.

Contributing

For information on contributing, please see our contribution guidelines. 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.