twitter / finagle

A fault tolerant, protocol-agnostic RPC system

playframework / playframework

The Community Maintained High Velocity Web Framework For Java and Scala.

gatling / gatling

Modern Load Testing as Code

http4s / http4s

A minimal, idiomatic Scala interface for HTTP

softwaremill / tapir

Rapid development of self-documenting APIs

guardian / frontend

The Guardian DotCom.