What is json?

serde_json is a Rust library for working with JSON, the text-based data format used across most web APIs and config files. JSON lets programs exchange structured information like names, numbers, and nested lists in a format both humans and machines can read. The library handles three different ways of interacting with JSON. The first is raw text, for when you receive a JSON string from a server or a file and want to pass it along unchanged. The second is a flexible in-memory structure that lets you look up any field by name without defining the shape of the data upfront. The third is conversion directly into Rust types you define yourself. That third approach is what the library is best known for. You describe your data as a Rust struct, add a short annotation to it, and the library can convert a JSON string into a properly typed value with a single function call. If the incoming data is missing a required field or has the wrong type, you get an error you can handle rather than silent incorrect behavior. The Rust compiler and most editors can then check your code against those types, catching typos in field names before you ever run the program. The library also includes a shorthand for writing JSON inline in Rust code. It lets you build a JSON object using syntax that looks like JSON, useful for constructing messages to send to an API without manually joining strings. The library is part of the broader Serde framework, which covers many serialization formats beyond JSON, but this repository focuses on the JSON piece specifically.