JSON Integration with HTTP Routing

This is detailed in more depth in the HTTP Requests, HTTP Responses and Message Body Components sections of the documentation.


When using a custom “request” case class as a route callback’s input type, Finatra will parse the incoming request body into the case class using the server’s configured ScalaObjectMapper.

Similar to declaratively parsing a GET request (described above), Finatra will perform validations and return a 400 BadRequest with a list of all accumulated errors in JSON format.

Suppose you wanted to handle a POST of the following JSON (representing a group of tweet ids):

  "name": "EarlyTweets",
  "description": "Some of the earliest tweets on Twitter.",
  "tweetIds": [20, 22, 24],
  "dates": {
    "start": "1",
    "end": "2"

You could create and use the following case classes:

import jakarta.validation.constraints.{NotEmpty, Past}
import java.util.Date

case class GroupRequest(
  @NotEmpty name: String,
  description: Option[String],
  tweetIds: Set[Long],
  dates: Dates) {

case class Dates(
  @Past start: Date,
  @Past end: Date)

This case class could then used as the input to a Controller route callback:

post("/tweets") { request: GroupRequest =>


To return a JSON response you can simply return a case class as the return of your route callback. The default behavior will be to render this case class as a JSON response.

See the HTTP Responses section for more information.