How to use the JSON to Swift
- Paste a JSON sample in the input — Swift is already selected.
- Set the root type name and options such as optional fields and date detection.
- Copy the generated Swift code into your project.
JSON to Swift structs
Each JSON object becomes a Swift struct conforming to Codable, with camelCase properties and a CodingKeys enum when the JSON uses snake_case or other key styles. Optional fields become optionals (String?) and arrays become [T].
Decoding
try JSONDecoder().decode(Root.self, from: data) reads the JSON. For ISO 8601 dates set decoder.dateDecodingStrategy = .iso8601; for snake_case keys you can also use .convertFromSnakeCase.
Private by design
The conversion runs entirely in your browser — API responses with customer or internal data are never uploaded.
Tools that pair well with the JSON to Swift
- JSON Validator — Paste JSON to check whether it is valid.
- JSON Schema Validator — Paste a schema and some JSON to see exactly which values break which rule — or generate a starting schema from example data.
- Mock Data Generator — Create up to 10,000 rows of realistic test data — users, products, orders, addresses, companies or nested API records — or build your own schema.
- JSONPath Tester — Type a JSONPath query and instantly see what it selects — with the exact path of each match.
Frequently asked questions
How are nested JSON objects converted to Swift?
Each nested object becomes its own named struct, named after its key, and referenced from the parent. Arrays become typed lists of the element type.
What happens with fields that are missing or null in some items?
When you paste an array of objects, fields that are missing or null in some items are marked optional (nullable), so the generated code matches real API responses.
Is my JSON uploaded?
No. The conversion runs entirely in your browser, so API responses with private data never leave your device.
Can I install JSON to Swift as a web app and use it offline?
Yes. JSON to Swift is an installable web app (PWA) — installed from your browser, not downloaded from an app store. Click Install app at the top of this page in Chrome or Edge (Windows, macOS, Linux, ChromeOS) or on Android, use Share → Add to Home Screen on iPhone and iPad, or File → Add to Dock in Safari 17+ on a Mac. It then opens in its own window with its own icon, and because it runs entirely in your browser it keeps working offline. Firefox on desktop can’t install web apps. How installing works.