Two years ago I wrote an article about working with JSON in Rust. JSON (de)serialization support was then baked in the standard library. However, at that time Rust was at version 0.13 and a lot of things happened since then. Mainly, the rustc-serialize crate got pulled out of the core libraries, but kept its close relation to the rustc compiler itself. (Hence the slightly awkward name.)

Meanwhile, a new contender arose: serde. It is also a generic serialization framework for Rust. It's more modern, actively maintained and gets lots of love from the community. There's a selection of supported data formats, including JSON, YAML, MessagePack as well as several others. Even the official docs for rustc-serialize say (emphasis mine):

While this library is the standard way of working with JSON in Rust, there is a next-generation library called Serde that's in the works (it's faster, overcomes some design limitations of rustc-serialize and has more features). You might consider using it when starting a new project or evaluating Rust JSON performance.

Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

JSON is a workhorse data format of the modern Web. Originating from the JavaScript world, it gained a lot of traction and at the moment it's usually the first choice of a Web developer for a data interchange format. Not only Web - once JavaScript-only, JSON support is now ubiquitous. A lot of languages ship with JSON parsers in the standard libraries, and when it's not the case, surely someone has already built a third party library. In case of Rust, JSON support comes out of the box in the serialize::json module.