JSON to Dart Class Generator Online — Free Dart Model Generator

How to JSON to Dart Online

1. 1

   Paste valid JSON into the input area on the left.

2. 2

   Set the root class name (defaults to 'Root') using the option field.

3. 3

   Toggle null-safety and JSON serialization options to match your Dart project requirements.

4. 4

   Click Convert or press ⌘↵ (Mac) / Ctrl+Enter (Windows) to generate Dart model classes.

5. 5

   Copy the generated Dart code with the copy button or download it as a .dart file.

JSON to Dart Features

• ✓

  Generates null-safe Dart classes from any JSON object or array.

• ✓

  Supports nested objects — creates separate named classes for each nested structure.

• ✓

  Optional json_serializable annotations (@JsonSerializable, fromJson, toJson) for use with build_runner.

• ✓

  Smart type inference: string, int, double, bool, List, and nullable variants.

• ✓

  Root class name is configurable; nested class names are derived from JSON keys.

• ✓

  Handles JSON arrays of objects by inferring the element type.

• ✓

  Works entirely in your browser — JSON never leaves your device.

• ✓

  Keyboard shortcut ⌘↵ for instant conversion.

Frequently Asked Questions

What is JSON to Dart conversion?

JSON to Dart conversion generates Dart class definitions (model classes) from a JSON sample. Instead of writing data classes by hand, you paste your API response and get strongly-typed Dart code with correct field types, constructors, and optional JSON serialization helpers.

Does the generated code support null safety?

Yes. When null-safety is enabled (the default), field types are marked nullable (String?) only when the JSON value is null. Non-null values produce non-nullable types. Disable the option if you are targeting older Dart SDK versions that predate null safety.

What is json_serializable?

json_serializable is a Dart package that generates fromJson and toJson methods automatically via code generation (build_runner). Enabling the option adds @JsonSerializable() annotations and the necessary factory constructor so you can run dart run build_runner build to generate the serialization glue code.

Is my JSON data safe?

All conversion runs in your browser using pure JavaScript. No JSON is ever sent to a server. Your data stays completely private.

Can it handle nested JSON objects?

Yes. Each nested JSON object becomes its own Dart class. The parent class references the child class by name, and all classes are output together in the same file.

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