Open Source Scala JSON Software

circe is a JSON library for Scala (and Scala.js).

Scala macros for compile-time generation of safe and ultra-fast JSON codecs. This library had started from macros that reused jsoniter (json-iterator) for Java reader and writer but then the library evolved to have its own core of mechanics for parsing and serialization. The idea to generate codecs by Scala macros and main details was borrowed from Kryo Macros and adapted for the needs of the JSON domain. Validate parsed values safely with the fail-fast approach and clear reporting, provide configurable limits for suboptimal data structures with safe defaults to be resilient for DoS attacks, generate codecs that create instances of a fixed set of classes during parsing to avoid RCE attacks.

ZIO Json is a fast and secure JSON library with tight ZIO integration. The goal of this project is to create the best all-round JSON library for Scala. Extreme performance is achieved by decoding JSON directly from the input source into business objects (docs/inspired by plokhotnyuk). Although not a requirement, the latest advances in Java Loom can be used to support arbitrarily large payloads with near-zero overhead. Best-in-class security is achieved with an aggressive early exit strategy that avoids costly stack traces, even when parsing malformed numbers. Malicious (and badly formed) payloads are rejected before finishing reading.

Airframe is an essential building block for developing applications in Scala, including logging, object serialization using JSON or MessagePack, dependency injection, HTTP server/client with RPC support, functional testing with AirSpec, etc. Airframe RPC supports seamless integration of servers and clients using Scala as RPC interfaces. AirSpec is a simple unit testing framework for Scala and Scala.js. You can use public methods in your classes as test cases. There is no need to remember complex DSLs for writing tests in Scala. Retrying HTTP requests for API calls is an essential technique for connecting microservices. airframe-control will provide essential tools for making your requests reliable with exponential backoff retry, jitter, circuit-breaker, rate control, etc. airframe-fluentd supports logging your metrics to fluentd in a type-safe manner. You just need to send your case classes as metrics for fluentd.

The term "jawn" comes from the Philadelphia area. It conveys about as much information as "thing" does. I chose the name because I had moved to Montreal so I remembered Philly fondly. Also, there isn't a better way to describe objects encoded in JSON than "things". Finally, we get a catchy slogan. Jawn was designed to parse JSON into an AST as quickly as possible. Currently, Jawn is competitive with the fastest Java JSON libraries (GSON and Jackson) and in the author's benchmarks, it often wins. It seems to be faster than any other Scala parser that exists (as of July 2014).

akka-http-json provides JSON (un)marshalling support for Akka HTTP. Use respective support trait or object, e.g. ArgonautSupport, FailFastCirceSupport, etc. into your Akka HTTP code which is supposed to (un)marshal from/to JSON. Don't forget to provide the type class instances for the respective JSON libraries, if needed.

spray-json is a lightweight, clean and efficient JSON implementation in Scala.