JSON to Dart

Generate Dart classes/structs automatically from a JSON object.

100% Client-Side Local Execution

Upload Data

Class Name:

1

{"id": 1, "name": "Omni", "isActive": true, "tags": ["tool", "web"]}

{"id": 1, "name": "Omni", "isActive": true, "tags": ["tool", "web"]}

class ResponseData {
  final int id;
  final String name;
  final bool isActive;
  final List<String> tags;
  ResponseData({
    required this.id,
    required this.name,
    required this.isActive,
    required this.tags,
  });
}

class ResponseData {
  final int id;
  final String name;
  final bool isActive;
  final List<String> tags;
  ResponseData({
    required this.id,
    required this.name,
    required this.isActive,
    required this.tags,
  });
}

What is JSON to Dart?

This free online tool turns a sample JSON payload into a ready-to-use model class (for Flutter) for Dart, so you can use this json to dart model tool to go straight from raw JSON to a typed model class without writing the boilerplate yourself. It is built around Dart's actual idiom — a Dart model class — rather than a generic one-size-fits-all class, and pairs naturally with dart:convert's jsonDecode plus manual fromJson/toJson methods for real-world (de)serialization. Use it for json to dart class online or any time you need flutter json to dart model, whether you're scaffolding a new Dart project or mapping an existing API response.

Technical Execution

Paste or upload a sample JSON object or array and the tool walks its structure field by field, inferring a concrete Dart type for each value — mapping basic JSON types to `String`, `int`/`double`, and `bool` as appropriate. For nested data, it generates a separate model class, complete with `fromJson` factory constructor and `toJson` method, for every nested JSON object, and types arrays as `List<T>` of the matching element type. On the naming side, it converts snake_case keys to Dart's camelCase field convention while keeping the original key inside the generated `fromJson`/`toJson` methods so Flutter's `http` responses still map correctly. For optional data, fields seen as `null`, or missing from some sample objects, are typed with Dart's nullable type syntax (`String?`, `int?`), matching Dart's sound null-safety requirement that every nullable field be declared explicitly.

Zero Data Storage Guarantee

Everything runs client-side in your browser: the sample JSON you paste in — which may contain real field names, endpoint shapes, or structure from a private API or project — is parsed and converted entirely on your device and is never uploaded to any server. Nothing you enter is logged, stored, or transmitted anywhere, so you can safely paste a real payload from an internal or unreleased API to generate an accurate Dart model class. Closing or refreshing the tab clears everything, since no copy of your data ever left your machine in the first place.

How to Use JSON to Dart (Step-by-Step Guide)

Copy a representative sample of your JSON (the more fields and nested objects it includes, the more complete the generated model class will be).
Paste it into the input panel of the JSON to Dart tool, or click "Upload" to load it from a json file.
Review the auto-detected root name, and rename it if you want the generated Dart model class to use a specific class or type name instead of the default.
Click "Generate" to produce the Dart model class, which appears instantly in the output panel with syntax highlighting.
Click "Copy" to copy the generated code to your clipboard, or "Download" to save it as a `.dart` file.
Paste the result into your Dart project and adjust field names or types if your data has edge cases the sample didn't cover.

Frequently Asked Questions (FAQ)

Q: How does this tool handle nested objects and arrays when converting JSON to Dart?

A: The tool generates a separate model class, complete with `fromJson` factory constructor and `toJson` method, for every nested JSON object, and types arrays as `List<T>` of the matching element type That keeps the generated code organized the way a Dart developer would structure it by hand, instead of flattening everything into one giant model class.

Q: What happens to fields that are nullable or missing from some records?

A: For optional data, fields seen as `null`, or missing from some sample objects, are typed with Dart's nullable type syntax (`String?`, `int?`), matching Dart's sound null-safety requirement that every nullable field be declared explicitly. If your sample only has one example object, fields that could be null in other records might not be detected as optional — paste a few varied samples (or an array of objects) for the most accurate result.

Q: Is this better than writing the model class by hand?

A: For anything beyond a trivial, flat payload, yes — writing `fromJson`/`toJson` boilerplate by hand for a nested Flutter model is one of the most repetitive parts of Flutter development, and it's a common source of bugs when an API response adds or renames a field. The generator produces the same result in seconds and gives you a correct starting point to refine, rather than a blank page.

Q: Is my JSON data safe to paste into this tool, especially if it's from a private API?

A: Yes. Everything runs client-side in your browser: the sample JSON you paste in — which may contain real field names, endpoint shapes, or structure from a private API or project — is parsed and converted entirely on your device and is never uploaded to any server. Nothing you enter is logged, stored, or transmitted anywhere, so you can safely paste a real payload from an internal or unreleased API to generate an accurate Dart model class. Closing or refreshing the tab clears everything, since no copy of your data ever left your machine in the first place.

Q: Can I use this as a convert json to dart model free?

A: Yes — the tool is commonly used as a convert json to dart model free, and works the same way whether you're converting a one-off response for a prototype or generating model code for a production project.

Q: Does the tool rename fields to match Dart naming conventions?

A: Yes. It converts snake_case keys to Dart's camelCase field convention while keeping the original key inside the generated `fromJson`/`toJson` methods so Flutter's `http` responses still map correctly, so the generated code reads naturally in Dart while still deserializing the original JSON correctly.

Q: What Dart library does the generated code work with?

A: The output is written to pair cleanly with dart:convert's jsonDecode plus manual fromJson/toJson methods, the most common choice for Dart developers handling JSON, so you can drop it into an existing project without changing your serialization setup.

Q: Does this tool work for deeply nested or large JSON samples?

A: Yes. The tool recurses through every level of nesting it finds and generates a complete set of linked model class definitions, not just the top level — though for very large samples, trimming it down to one representative record per array is usually enough to get an accurate result.

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