<iframe src="https://devtoolbox.dedyn.io/tools/json-to-dart" width="100%" height="600" frameborder="0" title="JSON to Dart Class Converter"></iframe>
JSON to Dart Class Converter
Generate Dart model classes from JSON data. Creates constructor, fromJson factory, and toJson method. Supports null safety, json_serializable annotations, nested objects, and arrays. Everything runs in your browser — your data stays private.
Examples:
Dart class definitions will appear here...
About JSON to Dart Class Conversion
Dart and Flutter require explicit class definitions for working with JSON data from APIs. Manually writing model classes with fromJson and toJson methods for complex API responses is tedious and error-prone. This tool automates the process, generating clean, idiomatic Dart model classes from any JSON input.
The converter inspects every value in your JSON and determines the correct Dart type. Nested objects become separate named classes with their own serialization methods. Arrays are analyzed to determine element types. Null values are handled with Dart's sound null safety, generating nullable types where appropriate.
Features
Generates Dart classes with constructor, fromJson factory, and toJson method
Full null safety support with nullable types (String?, int?)
Optional json_serializable annotations for code generation
Handles deeply nested objects with separate named classes
Detects array element types (primitives, objects, mixed uses dynamic)
Smart number detection: integers use int, decimals use double
Option to make all fields final for immutable models
Proper camelCase field naming with original JSON key mapping
Syntax-highlighted Dart output with color-coded keywords, types, and strings
100% client-side — your data never leaves your browser
The converter parses your JSON data and generates corresponding Dart class definitions. Each JSON object becomes a Dart class with a constructor, a fromJson factory constructor, and a toJson method. Nested objects create separate named classes. Arrays are analyzed to determine element types. JSON types map to Dart types: strings become String, integers become int, decimals become double, booleans become bool, and null values become nullable types (e.g., String?).
Does the converter support Dart null safety?▼
Yes. The converter fully supports Dart's sound null safety. When enabled, fields that have null values in your JSON are generated with nullable types (e.g., String? instead of String). The fromJson and toJson methods handle nullable fields correctly with null-aware operators. You can toggle null safety on or off depending on your project requirements.
Can I use the generated code with json_serializable?▼
Yes. Enable the json_serializable option and the converter will add @JsonSerializable() annotations, @JsonKey annotations for field name mapping, and the required part directive and imports. You can then use build_runner to generate the serialization code automatically. This is the recommended approach for larger Flutter projects.
Is my JSON data safe when using this converter?▼
Yes, completely. This JSON to Dart class converter runs 100% in your browser using client-side JavaScript. Your JSON data never leaves your computer and nothing is sent to any server. You can verify this by checking the network tab in your browser's developer tools, or even use the tool offline once the page has loaded.