What this does

Generates Swift struct (or class) declarations from a JSON sample. Turn Types only off to make them Codable and addCodingKeys, so JSONDecoder can read your payload directly.

Example

Input

{
  "id": 42,
  "name": "Ada",
  "verified": true,
  "tags": [
    "admin",
    "dev"
  ],
  "orders": [
    {
      "sku": "A1",
      "qty": 2
    },
    {
      "sku": "B2",
      "qty": 1,
      "note": "gift"
    }
  ]
}

Output with default options

import Foundation

// MARK: - Root
struct Root {
    let id: Int
    let name: String
    let verified: Bool
    let tags: [String]
    let orders: [Order]
}

// MARK: - Order
struct Order {
    let sku: String
    let qty: Int
    let note: String?
}

How values are mapped

Whole numbers become Int, other numbers Double, strings String, booleans Bool.
Arrays become [T]; a field missing from some objects becomes T?.
ISO 8601 timestamps become Date when date detection is on.
Arrays of mixed types become an enum with an associated value per type.

Options

Choose struct or class, internal or public access, andlet or var properties. Generate CodingKeys maps Swift-style names back to the original JSON keys when you want a Codable result.

Things to know

Property names become lowerCamelCase, so user_id turns intouserID. Swift has no way to decode a bare null value into a useful type, so a field that is always null becomes NSNull; replace it by hand once you know the real type.

Privacy

Generation runs in a Web Worker in your browser. The JSON is never uploaded.

JSON to Swift Codable Converter