JSON to Dart Class
LiveConvert JSON to Dart class definitions with fromJson/toJson for Flutter.
Understanding JSON (JavaScript Object Notation)
Dart is the language behind Flutter, Google's cross-platform UI framework. Flutter applications consume JSON from REST APIs using model classes with fromJson() factory constructors and toJson() methods. Converting JSON to Dart model classes generates the boilerplate code needed for JSON serialization — class properties, constructors, fromJson/toJson methods, and type-safe property access. This is a fundamental workflow for every Flutter developer integrating with backend APIs.
Use this free JSON to Dart converter to generate Dart class definitions from JSON data. Creates factory constructors with fromJson() and toJson() methods, null-safe Dart code compatible with Flutter development. Handles nested objects, lists, and arrays. Works like quicktype for Dart — paste your JSON and get ready-to-use Flutter model classes instantly.
The Devkitr JSON to Dart Model Converter generates Dart model classes with factory fromJson constructors and toJson methods from JSON data. Paste API response JSON to get Flutter-ready model classes with proper Dart types, null safety, and nested model handling.
In a typical development workflow, JSON to Dart Class becomes valuable whenever you need to convert json to dart class definitions with fromjson/tojson for flutter. Whether you are working on a personal side project, maintaining production applications for a company, or collaborating with a distributed team across time zones, having a reliable browser-based conversion tool eliminates the need to install desktop software, write one-off scripts, or send data to third-party services that may log or retain your information. Since JSON to Dart Class processes everything locally on your device, your data stays private and your workflow stays uninterrupted — open a browser tab, paste your input, get your result.
Key Features
Null Safety Support
Generates Dart null-safe code with nullable types (String?) and required keyword for non-nullable constructor parameters.
fromJson/toJson Methods
Creates factory constructors (fromJson(Map<String, dynamic>)) and serialization methods (toJson()) for each model class.
json_serializable Support
Optionally generates @JsonSerializable annotations and part directives for code generation with json_serializable package.
Nested Model References
Creates separate model classes for nested JSON objects with proper type references and recursive fromJson parsing.
How to Use JSON to Dart Class
Paste JSON Response
Enter JSON from your Flutter app's REST API, Firebase, or any backend service.
Select Generation Style
Choose between manual fromJson/toJson methods or json_serializable code generation annotations.
Review Model Classes
Check property types, null safety annotations, and nested model class definitions for accuracy.
Copy Dart Code
Copy the model classes into your Flutter project's models directory.
Use Cases
Flutter REST API Integration
Generate Dart models for REST API responses to use with http, dio, or Chopper packages for type-safe API consumption.
Firebase Data Models
Create Dart model classes matching Firebase Firestore document structures for type-safe Cloud Firestore data access.
GraphQL Response Types
Generate Dart models for graphql_flutter query responses with proper type mapping and nested object handling.
Local JSON Parsing
Create models for parsing local JSON assets (configuration, localization, sample data) bundled in Flutter apps.
Pro Tips
Use the required keyword for non-nullable constructor parameters in Dart null-safe models to enforce data completeness.
Add @JsonKey(name: "field_name") annotations when JSON keys differ from Dart property names (snake_case to camelCase).
For large APIs, consider using json_serializable with build_runner for compile-time code generation instead of manual fromJson methods.
Create a base Response<T> wrapper model for paginated and status-wrapped API responses.
Common Pitfalls
Not handling null values in fromJson constructors
Fix: Use null-aware operators: json["key"] as String? for nullable fields. Unhandled nulls cause runtime type casting exceptions in Dart.
Using Map<String, dynamic> without model classes
Fix: Raw maps lose type safety and IDE support. Always create model classes for structured JSON data accessed in multiple places.
Not generating toJson for models used in POST/PUT requests
Fix: Models sent to APIs need toJson() serialization. Ensure every model used in request bodies has a toJson method alongside fromJson.
Frequently Asked Questions
QHow do I convert JSON to Dart?
Paste your JSON data and the converter instantly generates Dart class definitions with fromJson() and toJson() methods, ready for Flutter development.
QIs this JSON to Dart converter like quicktype?
Yes. Similar to quicktype, it generates typed Dart model classes from JSON data with proper serialization methods and null safety support.
QDoes the generated Dart code support null safety?
Yes. All generated code uses Dart null safety syntax with required parameters and nullable types where appropriate.
QCan I convert nested JSON to Dart classes?
Yes. Nested JSON objects are converted to separate Dart classes with proper type references and fromJson/toJson methods for each level.
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