s2n-quic
An implementation of the IETF QUIC protocol
s2n-quic is AWS’s open-source implementation of the IETF QUIC transport protocol, written in Rust and designed for performance, security, and modern usage. QUIC is a UDP-based, multiplexed, encrypted transport layer that underpins HTTP/3 and addresses issues such as head-of-line blocking and faster handshake times compared to TCP+TLS. This library integrates with AWS’s s2n-tls or rustls for the TLS 1.3 handshake and leverages Rust’s memory and thread safety guarantees to deliver a robust implementation. It is built with configurability in mind—you can tune congestion control (like CUBIC), pacing, packet size discovery, and other advanced network behaviors. Extensive testing (unit, fuzz, interop) ensures protocol compliance and interoperability with other implementations. Because it is open-source under Apache 2.0, organizations can integrate it into services where low latency, multiple streams, or mobility (connection migration) matter.