JSON to Rust Struct: GitHub User API

Real-World Example: GitHub User Endpoint

The GitHub REST API's GET /users/{username} returns a rich JSON payload with nested objects, optional fields, and timestamps. It is a perfect mid-sized example for the converter.

Sample response (trimmed)

{
  "login": "octocat",
  "id": 583231,
  "node_id": "MDQ6VXNlcjU4MzIzMQ==",
  "avatar_url": "https://avatars.githubusercontent.com/u/583231?v=4",
  "html_url": "https://github.com/octocat",
  "type": "User",
  "site_admin": false,
  "name": "The Octocat",
  "company": "@github",
  "blog": "https://github.blog",
  "location": "San Francisco",
  "email": null,
  "bio": null,
  "public_repos": 8,
  "followers": 9001,
  "following": 9,
  "created_at": "2011-01-25T18:44:36Z",
  "updated_at": "2024-05-10T17:20:11Z"
}

Auto-generated Rust (lightly edited)

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GitHubUser {
    pub login: String,
    pub id: i64,
    pub node_id: String,
    pub avatar_url: String,
    pub html_url: String,
    #[serde(rename = "type")]
    pub user_type: String,
    pub site_admin: bool,
    pub name: Option<String>,
    pub company: Option<String>,
    pub blog: Option<String>,
    pub location: Option<String>,
    pub email: Option<String>,
    pub bio: Option<String>,
    pub public_repos: i32,
    pub followers: i32,
    pub following: i32,
    pub created_at: String,
    pub updated_at: String,
}

Notable adjustments

• The JSON key type collides with a Rust keyword, so the converter emits r#type plus a #[serde(rename = "type")]. The example above renames the field to user_type for readability.
• name, company, blog, location, email, and bio can be null (some users hide them), so each was promoted to Option<String> after pasting.
• created_at and updated_at use ISO 8601 strings. To get real DateTime<Utc> values, replace String with chrono::DateTime<chrono::Utc> and add chrono = { version = "0.4", features = ["serde"] } to Cargo.toml.

Calling the API

let resp: GitHubUser = reqwest::get("https://api.github.com/users/octocat")
    .await?
    .json()
    .await?;

println!("{} has {} followers", resp.login, resp.followers);

Lessons learned

This single endpoint exercises six features of the converter at once: snake_case mapping, integer width selection, Option promotion, keyword escape, struct naming, and serde derives. Use it as the template for your own real-world API client work.