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JSON to Dart Class

Convert JSON data to Dart class definitions. Infer nested classes, List types, null safety, Freezed and JsonSerializable annotations. Runs entirely in your browser — your data never leaves your machine.

json dart flutter converter code-generator mobile

Published May 29, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Paste any JSON data and instantly get Dart class definitions. The tool infers types from values, handles nested objects, arrays, null values, and mixed types. Configure the root class name, final/mutable fields, null safety, and optional @freezed or @JsonSerializable annotations for code generation compatibility.

Features

  • Plain class generation: class with fields, constructor, fromJson factory, and toJson method
  • camelCase properties: Dart-idiomatic naming, with snake_case and kebab-case keys converted automatically
  • Null safety: nullable types with ? suffix for null JSON values
  • final / mutable fields: choose immutable or mutable properties
  • @freezed support: generate Freezed-compatible immutable data classes with _$ClassName mixin
  • @JsonSerializable support: generate json_serializable-compatible classes with @JsonKey annotations
  • Nested class inference: objects within objects generate separate named classes
  • Accurate type mapping: String, int, double, bool, dynamic, List<T>, Map<String, dynamic>
  • fromJson / toJson: automatic serialization methods with nested class support
  • 5 example payloads: simple, nested, array, API response, Flutter model
  • Private: runs entirely in the browser — no data transmitted

Use Cases

  • Quickly generating Dart model classes for API response data
  • Bootstrapping Flutter app data models from JSON fixtures
  • Converting JSON config files to typed Dart classes
  • Learning how JSON structures map to Dart types
  • Generating Freezed or json_serializable-compatible data classes