JSON to Code Models

Turn an API response into typed models in the language you use.

Private by design

Your inputs stay on your device and are not sent to our servers. Optional usage analytics does not receive your files or tool inputs.

JSON to Code Models

Typed models from sample JSON

Sample JSON

Code

The result appears here.

Options

Top-level type name

Mark missing or null fields optional

A model is a type definition that matches the shape of your JSON, so your code can read API responses safely. The tool reads your sample, works out each field's type, and writes the types with the right JSON names for each language.

Paste a list of several items so the tool can spot fields that are sometimes missing.
Generated code uses common libraries: Jackson (Java), System.Text.Json (C#), kotlinx.serialization (Kotlin), Codable (Swift), serde (Rust).
Whole numbers become integers; any decimal makes the field a float.

Every value in your sample is typed, objects in a list are merged into one type, and nested objects become their own named types. Names are converted to each language's style, and reserved words are escaped. Runs entirely in your browser.

Preparing tool

How to use JSON to Code Models

Paste a sample of the JSON your API returns.
Pick the language and the name of the top-level type.
Copy the generated types into your project.

Read the detailed guide →

What are the limits of JSON to Code Models?

Types are guessed from your sample, so check them against the API docs. Mixed-type values become a generic type, and fields missing from some items are marked optional. Handles up to 2 MB. Your data stays on your device.