libraryDependencies += "com.iravid" %% "play-json-cats" % 1.1.0

import cats.implicits._
import com.iravid.playjsoncats.implicits._
import play.api.libs.json._

case class Person(name: String, i: Int)

val rn: Reads[String] = Reads(j => (j \ "name").validate[String])
val ri: Reads[Int] = Reads(j => (j \ "i").validate[Int])
val rp: Reads[Person] = (rn, rp).mapN(Person)

val res: JsResult[Person] = rp.reads(Json.parse("""
  { "name": "iravid", "i": 42 }
"""))