How to Format JSON in Rust

Feb 06, 2026 3 min read

The standard way to work with JSON in Rust is to use the serde and serde_json crates. By using serde_json::to_string_pretty, you can effortlessly serialize your structs or maps into an indented string.

Example Code

Rust

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug)]
struct User {
    name: String,
    age: u8,
    city: String,
    skills: Vec<String>,
}

fn main() {
    let user = User {
        name: String::from("John"),
        age: 30,
        city: String::from("New York"),
        skills: vec![String::from("Rust"), String::from("WASM")],
    };

    match serde_json::to_string_pretty(&user) {
        Ok(formatted_json) => println!("{}", formatted_json),
        Err(e) => println!("Error formatting JSON: {}", e),
    }
}

Common Use Cases

Creating CLI outputs for systems written in Rust
Formatting serialized API models locally
Writing structured readable debug files to disk

💡 Pro Tips for Rust

Make sure you enable the derive feature on the serde crate inside your Cargo.toml.
If you are writing straight to a file or stdout stream you should use serde_json::to_writer_pretty instead to save memory allocation mapping to a huge string.

Professional JSON Tools

Developing in Rust requires precision. Use our validator to ensure your sample JSON files are strictly compliant before running <code>serde</code>.

Check Validator Format JSON