Serde: Deriving, JSON & Field Attributes

Serde ("SERialize/DEserialize") is the de facto standard Rust framework for converting Rust data structures to and from formats like JSON, YAML, and more. Its generic core plus separate format crates (serde_json, serde_yaml, bincode) let one derived struct serialize to many formats.

Deriving Serialize/Deserialize

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct User {
    name: String,
    age: u32,
}

let json = serde_json::to_string(&user)?;
let user: User = serde_json::from_str(&json)?;

// The derive macro generates the conversion code at compile time --
// no runtime reflection needed, unlike some other languages' serializers

Strict Typing Catches Bad Data Early

A type mismatch or missing required field produces an explicit Result::Err at the parsing boundary -- not a subtle downstream bug from silently misinterpreted data.

Field Attributes

#[derive(Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
struct Profile {
    user_name: String,               // -> "userName" in JSON

    #[serde(default)]
    bio: String,                     // falls back to Default if missing

    #[serde(skip_serializing_if = "Option::is_none")]
    avatar_url: Option<String>,      // omitted from output entirely if None
}