Play JSON is a powerful Scala JSON library, originally developed by the Play team for use with Play Framework. It uses Jackson for JSON parsing and has no Play dependencies.

This is a fork of the JVM version of play-json that supports Jackson 2.17 and above. Read the core play-json docs if you need to see how the code works.

The differences from the core play-json are pretty small.

• only the JVM version of the main play-json lib is published here - for other libs use the playframework ones
• Jackson 2.17.3 (v3.1.x) or Jackson 2.18.2 (v3.2.x) - its StreamReadConstraints are applied and the default limits may be too low for some JSON inputs
• there is a dependency on com.typesafe config lib to allow users to configure behaviour
  • see reference.conf
• performance improvement for serializing numbers (playframework#1074)
• optional support for Jackson's fast decimal parser

The biggest risk that your JSON inputs will not parse are:

• deeply nested docs
• docs that have JSON values with more than 20m chars.
• you can configure bigger limits

• There are no Play releases that support versions of Jackson above 2.14
• StreamReadConstraints is the biggest issue but if the new Jackson defaults are ok and you are in a position to test the upgrade before you go to production, then you should be ok to just upgrade Jackson libs
• Beware that jackson-module-scala has a check that validates that version of jackson-databind has a compatible version (based on the minor version in semantic versioning). You should use the jackson-bom if your build tool supports BOMs. sbt does not support BOMs (unless you use the here-sbt-bom plugin). You can use use dependencyTree checks using your build tool to find mismatches between Jackson lib versions and add explicit dependencies on any lib that has an out of date dependency.
• You can use this fork of play-json and modify your application.conf if you need to add adjust the StreamReadConstraints settings
• In some use cases, Play uses its own Jackson ObjectMapper and not play-json. You may need to inject an updated ObjectMapper if you are hitting constraint exceptions. This needs to be done at JVM startup before you initiate Play.

val streamReadConstraints = StreamReadConstraints
  .builder()
  .maxNestingDepth(Integer.MAX_VALUE)
  .maxNumberLength(Integer.MAX_VALUE)
  .maxStringLength(Integer.MAX_VALUE)
  .build()
val testMapper = play.libs.Json.newDefaultMapper()
testMapper
  .getFactory()
  .setStreamReadConstraints(streamReadConstraints)
play.libs.Json.setObjectMapper(testMapper)

• play-json-jsoniter - needs some small code changes when you switch from play-json (see the tests in its GitHub repo)
• smithy4play

To get started, you can add play-json as a dependency in your project:

• sbt

  libraryDependencies += "com.github.pjfanning" %% "play-json" % -version-

• Gradle

  compile group: 'com.github.pjfanning', name: 'play-json_2.13', version: -version-
  

• Maven

  <dependency>
    <groupId>com.github.pjfanning</groupId>
    <artifactId>play-json_2.13</artifactId>
    <version>-version-</version>
  </dependency>

Play JSON supports Scala 2.12, 2.13 and Scala 3.3+. Choosing the right JAR is automatically managed in sbt. If you're using Gradle or Maven then you need to use the correct version in the artifactId.