Play Framework

Play was one of the first JVM frameworks to embrace reactive, non-blocking I/O throughout — no thread blocking, no synchronous calls. Its hot-reload, type-safe routing, and Twirl templates made Scala web development productive. Used at LinkedIn, Walmart, and many data-heavy applications requiring high concurrent throughput. Play 3 is built on Pekko (the Apache fork of Akka).

Quick start

sbt new playframework/play-scala-seed.g8
# Follow prompts for project name
cd my-app
sbt run

// app/controllers/PostController.scala
package controllers

import javax.inject._
import play.api._
import play.api.mvc._
import play.api.libs.json._

case class Post(id: Long, title: String, body: String)
object Post { implicit val format: OFormat[Post] = Json.format[Post] }

@Singleton
class PostController @Inject()(val controllerComponents: ControllerComponents)
  extends BaseController {

  private var posts: Seq[Post] = Seq(Post(1, "Hello Play", "Getting started."))

  def list = Action {
    Ok(Json.toJson(posts))
  }

  def create = Action(parse.json) { request =>
    request.body.validate[Post].fold(
      errors => BadRequest(JsError.toJson(errors)),
      post => {
        val newPost = post.copy(id = posts.length + 1)
        posts = posts :+ newPost
        Created(Json.toJson(newPost))
      }
    )
  }
}

# conf/routes
GET   /posts         controllers.PostController.list
POST  /posts         controllers.PostController.create

When to use

Play Framework suits Scala and Java teams building high-throughput reactive services, especially when already using the Akka/Pekko ecosystem. It’s particularly strong for streaming and data-heavy APIs. For most Java teams, Spring Boot is the more practical choice with a larger talent pool. For Scala teams building purely functional services, http4s or ZIO HTTP are more idiomatic. Play’s hot-reload and type-safe routing remain developer-friendly advantages.