What does this tool do?
JSON to Dart Class generates Dart classes from a sample JSON payload, letting Flutter and Dart developers stand up their model layer in seconds. It picks the right Dart type for each field and builds classes that typically include fromJson/toJson conversion methods, removing the need to parse API responses by hand.
How to use it
- Paste or type your data into the left field.
- The result is generated instantly on the right.
- Use the Copy button to grab the output.
fromJson and toJson methods
The generated Dart classes include a fromJson factory constructor that builds an object from a JSON map and a toJson method that turns the object back into a map. This lets you convert responses from http or dio directly into type-safe models in your Flutter app. Field names are converted to camelCase while the original JSON keys are preserved inside the conversion methods, so your code stays aligned with the server contract.
Nested structures and lists
Nested JSON objects are turned into separate Dart classes, and the parent class holds those types as fields. JSON arrays are modeled as List<T>; for lists of objects, fromJson uses .map to parse each element into the matching class. This structure lets you represent deep data models in Flutter cleanly, readably, and reusably, and the output usually compiles straight away when you paste it in.
Frequently asked questions
Do the generated classes include fromJson/toJson?
Yes, classes come with a fromJson constructor that builds an object from a JSON map and a toJson method that converts it back, ready to drop into your Flutter API layer.
Does this replace json_serializable?
Because the generated code includes hand-written serialization, it needs no build_runner. For many models you may prefer code-generation packages, but for small projects you can use this output directly.
How are nullable fields handled?
Fields that may be null or are ambiguous can be marked as nullable types (for example String?). You can fine-tune the output for null safety after copying it.
Is JSON to Dart Class free?
Yes. JSON to Dart Class and all 300+ tools on MagmaNex are completely free with no signup or account required.
Is my data safe?
Yes. Everything runs locally in your browser. The data you enter is never sent to a server, stored, or shared.
Does it work on mobile?
Yes. JSON to Dart Class works on phones, tablets and desktops — no app download needed.
🔒 Privacy: everything runs in your browser, your data is never sent to a server.