[](https://microsoft.github.io/msquic/) [](https://github.com/microsoft/msquic/actions/workflows/build.yml?query=branch%3Amain) [](https://github.com/microsoft/msquic/actions/workflows/test.yml?query=branch%3Amain) [](https://github.com/microsoft/msquic/actions/workflows/stress.yml?query=branch%3Amain) [](https://codecov.io/github/microsoft/msquic)  [](https://bestpractices.coreinfrastructure.org/projects/4846) [](https://discord.gg/YGAtCwTSsc) [](https://crates.io/crates/msquic) [](https://www.nuget.org/profiles/msquic) MsQuic is a Microsoft implementation of the [IETF QUIC](https://datatracker.ietf.org/wg/quic/about/) 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 [](https://tools.ietf.org/html/rfc9000) [](https://tools.ietf.org/html/rfc9001) [](https://tools.ietf.org/html/rfc9002) [](https://tools.ietf.org/html/rfc9221) [](https://tools.ietf.org/html/rfc9287) [](https://tools.ietf.org/html/rfc9368) [](https://tools.ietf.org/html/rfc9369) [](https://tools.ietf.org/html/draft-ietf-quic-load-balancers) [](https://tools.ietf.org/html/draft-ietf-quic-ack-frequency) [](https://tools.ietf.org/html/draft-banks-quic-disable-encryption) [](https://tools.ietf.org/html/draft-banks-quic-performance) [](https://tools.ietf.org/html/draft-banks-quic-cibir) 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](https://docs.microsoft.com/en-us/windows-hardware/drivers/network/introduction-to-receive-side-scaling)) support. * UDP send and receive coalescing support. # Documentation * For platform support details, see the [Platforms docs](./docs/Platforms.md). * For release details, see the [Release docs](./docs/Release.md). * For performance data, see the [Performance dashboard](https://aka.ms/msquicperformance). * For building the library, see the [Build docs](./docs/BUILD.md). * For testing the library, see the [Testing docs](./docs/TEST.md). * For using the API, see the [API docs](./docs/API.md) or the [Sample](./src/tools/sample/sample.c). * For deploying QUIC, see the [Deployment docs](./docs/Deployment.md). * For diagnosing issues, see the [Diagnostics docs](./docs/Diagnostics.md) and the [Trouble Shooting Guide](./docs/TSG.md). * For other frequently asked questions, see the [FAQs](./docs/FAQ.md). # Contributing For information on contributing, please see our [contribution guidelines](./.github/CONTRIBUTING.md). Feel free to take a look at our [Good First Issues](https://github.com/microsoft/msquic/labels/good%20first%20issue) list if you're looking for somewhere to start. If you'd just like to talk, come chat with us [on Discord](https://discord.gg/YGAtCwTSsc).