{ } JSON Workbench0 network requests. Check DevTools

"JSON to Swift":{ }

Paste a JSON sample and get clean Swift structs. Nested objects become named types, arrays become typed collections, and nullable fields are handled. Powered by quicktype's inference engine running 100% in your browser: zero network requests, so real API payloads stay on your machine.

What is a JSON to Swift converter?

Hand-writing structs for an API response is slow and error-prone. This tool infers Swift structs from a JSON sample: nested objects become named types, arrays become typed collections, and null/missing values become optional fields. It runs quicktype's inference engine entirely in your browser, so real API payloads (often containing user data or credentials) never leave your machine.

Swift mapping notes

  • Value-type structs with immutable let properties.
  • Integers map to Int and decimals to Double; nullable or missing values become optionals (String?).
  • Add Codable conformance and Swift's JSONDecoder parses matching JSON directly.

How to use

  1. Paste a JSON sample (an API response works well) into the Input pane.
  2. Generated Swift structs appear instantly. Nested objects become their own named types.
  3. Non-standard JSON (single quotes, trailing commas, comments) is auto-repaired first.
  4. Copy the code into your project.

Examples

JSON → Swift structs

Input
{
  "id": 42,
  "name": "workbench",
  "owner": { "email": "[email protected]", "active": true }
}
Output
struct Root {
    let id: Int
    let name: String
    let owner: Owner
}

struct Owner {
    let email: String
    let active: Bool
}

FAQ

How do I convert JSON to Swift types?

Paste any JSON sample. The structs are inferred from the values and nesting, entirely in your browser. Nothing is uploaded.

How are nested objects handled?

Each distinct nested object becomes its own named type, referenced from the parent, arrays of objects included.

What about optional or null fields?

Fields that are null or missing in parts of the sample are typed as optional/nullable in the generated code.

Can I paste multiple samples?

Paste an array of objects: the type is inferred from the union of all items, which catches optional fields a single sample would miss.

Are the structs Codable?

Add : Codable to each struct and JSONDecoder().decode(Root.self, from: data) will parse JSON with these exact keys.

Is my JSON uploaded?

No. Generation runs 100% in your browser via quicktype's engine. Check DevTools: zero network requests.

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