http4s
Scala library for typeful, functional and streaming HTTP servers and clients, built on FS2 and cats-effect.
http4s is a Scala library for HTTP servers and clients written as typed, functional and streaming code. It is built on FS2, manages its effects through cats-effect, and runs on the JVM. Its quickstart adds the Ember client and server modules to an sbt build through libraryDependencies, and its deployment page packages a service as an assembled jar that runs with java -jar.
Worth knowing
The README states that the blaze backend needs a JDK newer than 8u252. The quickstart runs the service as a server on a port, so it needs a host that keeps a process running.
Identity
Rendering and deploy
Releases
Adoption
Sources
- 2026-10-26: links, Categories, License
http4s.org/ - 2026-10-26: links, Written in, License, GitHub stars
api.github.com/repos/http4s/http4s - 2026-10-26: links, Install with, Runs as
http4s.org/v0.23/docs/quickstart.html - 2026-10-26: Maintainer, Runtime, License, License model
github.com/http4s/http4s/blob/series/0.23/README.md - 2026-10-26: Install with
http4s.org/v0.23/docs/deployment.html - 2026-10-26: License, First release
http4s.org/changelog.html - 2026-10-26: Current major version, Last release
api.github.com/repos/http4s/http4s/releases - 2026-10-26: Contributors
api.github.com/repos/http4s/http4s/contributors?per_page=1