spray/spray-json

A lightweight, clean and simple JSON implementation in Scala

sciss/play-json-sealed

Automatic sealed traits JSON format for play-json-alone

kondaurov-json/json_generic

Serialize/Deserialize generic types

kondaurov-json/json_schema

Build your own object schemas. This is like standard json schemas but not only for validation

sphereio/sphere-scala-libs

tethys-json/tethys

AST free JSON library for Scala