What JSON library to use in Scala?

Question

I need to build a JSON string, something like this:

[
  { 'id': 1, 'name': 'John'},
  { 'id': 2, 'name': 'Dani'}
]

val jArray = JsArray();
jArray += (("id", "1"), ("name", "John"))
jArray += (("id", "2"), ("name", "Dani"))
println(jArray.dump)

I need to be able to add rows to the jArray, something like jArray += ...

What is the closest library/solution to this?

Answer 1

Unfortunately writing a JSON library is the Scala community's version of coding a todo list app.

There are quite a variety of alternatives. I list them in no particular order, with notes:

1. parsing.json.JSON - Warning this library is available only up to Scala version 2.9.x (removed in newer versions)
2. spray-json - Extracted from the Spray project
3. Jerkson ± - Warning a nice library (built on top of Java Jackson) but now abandonware. If you are going to use this, probably follow the Scalding project's example and use the backchat.io fork
4. sjson - By Debasish Ghosh
5. lift-json - Can be used separately from the Lift project
6. json4s 💣 § ± - An extraction from lift-json, which is attempting to create a standard JSON AST which other JSON libraries can use. Includes a Jackson-backed implementation
7. Argonaut 💣 § - A FP-oriented JSON library for Scala, from the people behind Scalaz
8. play-json ± - Now available standalone, see this answer for details
9. dijon - A handy, safe and efficient JSON library, uses jsoniter-scala under hood.
10. sonofjson - JSON library aiming for a super-simple API
11. Jawn - JSON library by Erik Osheim aiming for Jackson-or-faster speed
12. Rapture JSON ± - a JSON front-end which can use 2, 4, 5, 6, 7, 11 or Jackson as back-ends
13. circe 💣 - fork of Argonaut built on top of cats instead of scalaz
14. jsoniter-scala - Scala macros for compile-time generation of ultra-fast JSON codecs
15. jackson-module-scala - Add-on module for Jackson to support Scala-specific datatypes
16. borer - Efficient CBOR and JSON (de)serialization in Scala

💣 = has not fixed security vulnerabilities, § = has Scalaz integration, ± = supports interop with Jackson JsonNode

In Snowplow we use json4s with the Jackson back-end; we've had good experiences with Argonaut too.