JSON to Swift Struct Generator

How to Use the Free Client-Side JSON to Swift Generator

This generator produces Swift structs with Codable conformance from a JSON sample, running entirely in your browser. It infers String, Int, Double, Bool, array, and optional types, and creates separate structs for nested objects.

The generated code targets Swift 5 and newer and relies on standard Codable behavior with matching property names.

1. Copy your JSON data and paste it into the input textarea above.
2. Toggle nullable detection for optional property generation.
3. Click Generate, then copy the Swift structs or download the .swift file.

When to Use JSON to Swift

iOS and macOS apps decode JSON into Codable structs, and mismatches between the struct and the payload cause decoding failures. This generator builds the structs straight from a response sample, so your networking layer decodes correctly on the first attempt. It is equally useful for creating Codable-compatible types from configuration files and for rapid prototyping of data models from mock JSON during development.

The generator targets Swift 5 and newer, producing immutable let properties inside structs that conform to Codable. Nullable fields become optionals with the question mark marker, nested objects become their own structs with proper type references, and arrays map to the expected collection types. Because the code uses default Codable behavior, keys match the JSON directly; if your JSON uses snake_case or custom names, a CodingKeys enum is the manual follow-up.

JSON to Swift Tips and Best Practices

1. Include every key that exists in your real data, since keys absent from the sample will not appear in the generated struct.
2. Add a CodingKeys enum manually when JSON keys use snake_case or custom naming that differs from Swift conventions.
3. Keep the import Foundation statement, since Codable conformance depends on it.
4. Review numeric types, adjusting Int versus Double to match the actual values in your payloads.

Why Client-Side Privacy Matters for iOS and macOS Data Model Generation

The JSON behind a mobile or desktop app often contains user profiles, identifiers, and personal data, and the structs you generate mirror those structures. Uploading the sample to an online generator exposes your app's data model externally.

This JSON to Swift generator runs entirely in your browser, so your sample data never leaves your device. You can build Codable models for consumer or internal apps without a third party seeing your payload shapes.