JSON to Swift Codable Structs
Apple's Codable protocol is the standard way to handle JSON in Swift. It's elegant and type-safe, but writing the structs and CodingKeys by hand is repetitive work — especially when your API uses snake_case naming and Swift expects camelCase properties. This tool handles the translation automatically.
Paste your JSON, and you get Swift structs conforming to Codable. Properties are named with proper Swift conventions (camelCase), and if the original JSON key differs, aCodingKeys enum is generated to map between them. All properties are optional by default because network responses can always surprise you with missing fields.
iOS and macOS JSON Handling
In iOS development, you typically decode JSON from URLSession responses usingJSONDecoder. The generated structs plug right into this workflow:
let decoder = JSONDecoder() decoder.keyDecodingStrategy = .convertFromSnakeCase let result = try decoder.decode(RootObject.self, from: data)If you're using the .convertFromSnakeCase strategy, you might not even need the CodingKeys enum — but our generator includes it as a safety net for keys that don't follow simple snake_case patterns (like abbreviations or numbers in keys).
SwiftUI and Combine
If you're building SwiftUI apps with Combine or async/await networking, having your model structs ready is the first step. Generate them from your API's actual response, add @Publishedproperties to your ViewModel, and you've got reactive data flowing from API to UI. The struct generation takes care of the boring part so you can focus on the UI.
Handling Optional Fields in Swift
Swift's type system makes JSON handling safer than most languages — but it also makes it stricter. If a field is marked non-optional and it's missing from the JSON, your entire decode fails. That's why we default to optionals. In production, you'll want to review which fields are truly required by your API and remove the ? from those properties for better compiler guarantees.
Related JSON Tools
Building a cross-platform app? Generate Kotlin data classes for Android. For Flutter, use JSON to Dart. Inspect your API responses with the JSON Viewer tree view.