What is JSON ➜ Dart Conversion?

JSON to Dart conversion lets you map JSON data into Dart model classes. This gives you:

• type safety
• autocompletion in IDE
• easier debugging
• cleaner API handling

Example JSON Data

{
  "id": 5,
  "name": "John Doe",
  "email": "john@example.com",
  "isActive": true
}

How to Parse JSON in Dart

Use dart:convert to decode JSON.

import 'dart:convert';

void main() {
  const jsonString = '{"id":1,"name":"Alice"}';

  final data = jsonDecode(jsonString);

  print(data['name']); // Alice
}

Create Dart Model Class

class User {
  final int id;
  final String name;
  final String email;

  User({
    required this.id,
    required this.name,
    required this.email,
  });

  factory User.fromJson(Map<String, dynamic> json) {
    return User(
      id: json['id'],
      name: json['name'],
      email: json['email'],
    );
  }

  Map<String, dynamic> toJson() {
    return {
      "id": id,
      "name": name,
      "email": email,
    };
  }
}

How to Parse JSON List in Dart

final jsonString = '[{"id":1,"name":"A"},{"id":2,"name":"B"}]';

final List<dynamic> decoded = jsonDecode(jsonString);

final users = decoded.map((u) => User.fromJson(u)).toList();

How to Read JSON File in Dart

import 'dart:convert';
import 'dart:io';

void main() async {
  final file = File('assets/user.json');

  final contents = await file.readAsString();

  final data = jsonDecode(contents);

  print(data);
}

In Flutter, put files inside assets/and add them in pubspec.yaml.

FAQ