JsonWriterInstances.scala

final case class Person(name: String, email: String)

object JsonWriterInstances {
  implicit val stringWriter: JsonWriter[String] =
  new JsonWriter[String] {
    def write(value: String): Json = JsString(value)
  }

  implicit val personWriter: JsonWriter[Person] =
  new JsonWriter[Person] {
    def write(value: Person): Json =
    JsObject(Map(
      "name" -> JsString(value.name),
      "email" -> JsString(value.email)
    ))
  }
}