JSON to Java Converter
Convert JSON to Java POJO classes for Java development
JSON Input
Java Output
What Is JSON to Dart?
Dart uses classes with fromJson and toJson for JSON serialization. This tool generates Dart classes from your JSON structure so you can parse API responses with dart:convert (jsonDecode) and map to typed objects. The JSON specification defines the input format.
Conversion runs in your browser. Set the class name and package in the config. Nothing is sent to a server. The generated classes work with Flutter, Dart VM, and server-side Dart projects.
How to Use This Tool
Paste or Upload JSON
Paste your JSON into the left editor or upload a file. Use the config panel to set the root Class Name and Package. The more representative your sample, the better the generated structure.
Review the Generated Classes
The right panel shows Dart classes. Use jsonDecode() and manual mapping, or add fromJson/toJson factory constructors. For Flutter, these models work with http, dio, or any HTTP client. Validate JSON first with JSON Validator if needed.
Copy or Download
Use Copy or Download. For formatting JSON first, use the JSON Formatter. For validation, use the JSON Validator.
JSON to Dart Examples
Here is an example of generating Dart classes from a JSON object.
Example: Subscriber record
JSON input:
Generated Dart output:
When JSON to Dart Helps
When building Flutter apps or Dart server projects that consume REST APIs, you need typed models for the response payload. Pasting a sample response here gives you Dart classes you can use with http, dio, or Chopper. Manually writing fromJson and toJson for complex nested JSON is tedious; this tool infers the structure from your sample.
For pulling out specific values from large responses first, use the JSON Path tool. For JSON Schema, use the JSON Schema Generator. Packages like json_serializable can generate serialization code from these classes.
Frequently Asked Questions
Nullable fields?
Use Type? for optional JSON fields. Enable nullable in the config if available. Dart's null safety requires explicit handling of absent values.
fromJson vs json_serializable?
This tool generates classes; you can add fromJson/toJson manually or use json_serializable to generate them via code generation. The package reduces boilerplate for complex models.
Is my data private?
Yes. Generation runs entirely in your browser. No JSON or code is sent to any server.
Can I use this with Flutter?
Yes. The generated classes work with Flutter's HTTP clients. Add them to your models folder and use with FutureBuilder or state management (Provider, Riverpod, Bloc).
What about freezed?
freezed generates immutable classes with copyWith. You can use this tool's output as a starting point and add freezed annotations for more advanced models.
Related Tools
For Dart JSON, see dart:convert and json_serializable. For JSON, see json.org and RFC 8259. For MDN JSON. For Postman API testing.