Http Backend Integrations

Http4s provides a frontend interface compatible with cats-effect, but it supports many different backend implementations

Backend Jdk Support Http4s Version(s) 100% Nonblocking Http Client Http Server Websocket Client Websocket Server Proxy support (Client)
Blaze 8+ 0.15+ ✅ Nonblocking http4s-blaze-client http4s-blaze-server ❌ ❌ ❌
Async Http Client 8+ 0.18+ ✅ Nonblocking http4s-async-http-client ❌ ❌ ❌ ✅
Ember 8+ 0.21+ ✅ Nonblocking http4s-ember-client http4s-ember-server ✅ ✅ ❌
Jdk11 Http Client 11+ 0.21+ ✅ Nonblocking http4s-jdk-http-client ❌ ✅ ❌ ✅
Jetty 8+ All (0.2+) ? ❌ http4s-jetty ✅
OkHttp 8+ 0.18+ ❌ Blocking http4s-okhttp-client ❌ ❌ ❌ ✅

Entity Integrations

Http4s has multiple smaller modules for Entity encoding and Decoding support of common types.