Step 1 - Encode

import 'dart:convert';

void main() {
  final map = {'name': 'Asha', 'score': 10};
  final text = jsonEncode(map);
  print(text);
}

• JSON object keys become strings. Dart Map keys must be strings for jsonEncode (or it throws).

Step 2 - Decode

import 'dart:convert';

void main() {
  final text = '{"name":"Asha","score":10}';
  final value = jsonDecode(text);
  print(value.runtimeType);
  print((value as Map)['name']);
}

• jsonDecode returns Object? at compile time; at runtime you usually get Map<String, dynamic>, List<dynamic>, String, num, bool, or null.

Step 3 - Pretty print (optional)

import 'dart:convert';

void main() {
  const encoder = JsonEncoder.withIndent('  ');
  print(encoder.convert({'a': 1, 'b': [2, 3]}));
}

Good habit

• Treat decoded data as untrusted: validate shape before using as your model.

Practice tasks

• Encode a List of maps and decode it back, then assert list length.
• Try jsonDecode('{bad') in try/catch and print FormatException.