JSON to Swift Codable Converter

Swift's Codable protocol makes JSON decoding nearly automatic — but only after you write the matching struct. For a real API response with nested objects, snake_case keys, and optional fields, hand-writing that struct is fiddly work. A JSON to Swift Codable converter produces it instantly and correctly.

OpenToolLab's converter generates a Codable struct for your JSON. Every field is typed from the sample: String, Int, Double, Bool, [Model] for arrays, and nested Codable structs for objects. Fields that are null or missing become optionals, so JSONDecoder skips them instead of throwing.

snake_case keys are handled the right way — through a CodingKeys enum that maps first_name to firstName. This is the standard Swift pattern, and it means your Swift properties stay camelCase while the JSON contract stays whatever the API returns.

The generator is shared with the other language targets, so the same JSON sample can produce a Swift Codable struct, a Kotlin data class, a Dart model, or a TypeScript interface from one window. Convert once, copy for each client you maintain.

Privacy is a core guarantee. All generation happens locally in your browser — your API responses and schemas never leave your device. Open the DevTools Network tab while converting and you will see zero requests.

The generated struct compiles as-is in Xcode. Add it to your models, decode with JSONDecoder().decode(MyModel.self, from: data), and you get a fully typed Swift value ready for SwiftUI or Combine pipelines.

Use it when adding a new endpoint to an iOS client, regenerating models after a backend change, or converting an OpenAPI example into Swift types. Paste the sample, generate, and keep your models in sync with the API contract.

OpenToolLab is a completely free JSON to Swift Codable converter with no signup and no limits. Paste, generate, and copy — privately and instantly, entirely in your browser.