Hyper

Hyper is a fast, correct, and low-level HTTP/1.1 and HTTP/2 implementation for Rust, serving as the HTTP engine for a large portion of the Rust networking ecosystem. Created by Sean McArthur in 2014 and maintained under the hyperium organization, it has over 14,600 stars as of 2026. Hyper provides both a client (for making HTTP requests) and server (for receiving HTTP requests) implementation, with full support for HTTP/1.1 (persistent connections, chunked transfer encoding, trailers, 100-continue), HTTP/2 (multiplexing, HPACK header compression, flow control, server push, trailers), and HTTP/3 via the h3 crate (QUIC transport). Key features include: streaming request and response bodies (enabling large file uploads and downloads without buffering entire payloads in memory), connection pooling for client-side connection reuse, TLS via rustls or native-tls, proxy configuration (HTTP, HTTPS, SOCKS5), WebSocket upgrades, server-sent events, configurable timeouts (connect, read, write, overall), automatic redirect following, cookie handling via cookie_store, and an extensible middleware layer via the Tower ecosystem. Hyper is designed as a building block rather than a complete HTTP client: Reqwest wraps Hyper for high-level usage, Axum and Warp build web servers on top of it, and Tonic provides gRPC over Hyper. Performance benchmarks show over 400,000 HTTP requests per second on a single core. Used at Cloudflare, AWS, Google, Stripe, and GitHub.