# microsoft/msquic

Cross-platform, C implementation of the IETF QUIC protocol, exposed to C, C++, C# and Rust.

Repository: https://github.com/microsoft/msquic
Canonical: https://ross.abutalabs.com/products/msquic
Language: C
License: MIT
License Family: permissive
Topics: quic, network-programming, protocol, c, secure, cross-platform, cpp, csharp, rust
Last push: 2026-08-26T22:03:05+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 97, longevity 100
- inputs: {"age_days": 2503, "days_push": 7, "days_rel": 20, "gap_med": 10.0, "n_releases_24m": 27}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4771, forks 690 (observed 2026-08-28T04:08:59.369835+00:00)

## What it is
MsQuic is Microsoft's cross-platform C implementation of the IETF QUIC transport protocol (RFC 9000), with API wrappers for C++, C#, and Rust. It provides a general-purpose QUIC library for building fast, secure client and server applications over UDP with TLS encryption.

## Use cases
- implement a QUIC server in C
- add QUIC transport to a Rust application
- use HTTP/3-style QUIC connections from C#
- build a low-latency secure transport layer over UDP
- replace TCP with QUIC for a custom protocol
- test QUIC protocol conformance
- implement stream multiplexing with 0-RTT connection setup

## When to choose
- you need a production-grade, cross-platform QUIC implementation maintained by Microsoft
- you want QUIC bindings for C, C++, C#, or Rust from one library
- you need fine-grained control over QUIC streams, connection settings, and TLS
- you require support for recent QUIC RFCs and drafts (datagrams, version negotiation, ACK frequency)

## When to avoid
- you just need HTTP/3 client or server functionality and prefer a higher-level HTTP library
- your stack is Python, Go, or Java with no native interop needs
- you need a pure managed or pure Rust implementation without a native C dependency
- you only need TCP/TLS and QUIC is not required

## Facets
- artifact type: library
- maturity: stable
- function: networking, security, http-client, http-server, sdk
- domain: networking, developer-tools, security, cross-platform
- platform: windows, cross-platform, c, cpp, rust, dotnet
- tags: quic, ietf-quic, rfc9000, tls, udp-transport, c-library, interop, linux, macos

## Member repositories
- microsoft/msquic (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:59.369835+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:18:48.183732+00:00, confidence not recorded.
  - readme: https://github.com/microsoft/msquic (fetched 2026-08-28T04:08:59.369835+00:00, sha 503165cf47cd)
- Data as of 2026-08-30T08:39:29.467469+00:00.