JSON to Dart Class Generator Online — Free Dart Model Generator
JSON to Dart
Convert JSON to Dart classes with null-safety and json_serializable support.
Free online JSON to Dart class generator. Paste any JSON object or array and instantly generate null-safe Dart classes with fromJson/toJson constructors. Supports json_serializable annotations, optional field detection, PascalCase class names, camelCase field names, and nested objects. Perfect for Flutter developers building data models from API responses. Runs entirely in your browser — no data is sent to a server.
Keywords: json to dart, json to dart converter, json to dart class, dart model generator, flutter json, dart fromjson, dart serialization, json_serializable dart, flutter data model, json to flutter class, dart null safety json, dart tojson, dart fromJson generator
Tags: json, dart, flutter, converter, class, model, generator
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How to JSON to Dart Online
Paste valid JSON into the input area on the left.
Set the root class name (defaults to 'Root') using the option field.
Toggle null-safety and JSON serialization options to match your Dart project requirements.
Click Convert or press ⌘↵ (Mac) / Ctrl+Enter (Windows) to generate Dart model classes.
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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