flutter-implement-json-serialization

Use the built-in dart:convert library with jsonDecode to parse the response string, cast the result to Map<String, dynamic>, and pass it to a fromJson factory constructor on your model class. Implement a toJson method for the reverse direction.

Use Flutter's compute() function to run parsing in a background isolate. Define a top-level parsing function, then call compute(parseFunction, response.body) so the main thread stays free for rendering frames.

Manual serialization with dart:convert fits simple data structures with few models and no nested complexity. For large schemas, deeply nested objects, or frequent model changes, code generation with json_serializable reduces boilerplate and maintenance.

jsonDecode returns dynamic because JSON structure is unknown at compile time. Always cast the result explicitly to Map<String, dynamic> for objects or List<dynamic> for arrays, and use pattern matching in fromJson to catch malformed data with a FormatException.

Throw an Exception when the status code indicates failure rather than returning null. Check for 200 on GET requests or 201 on POST requests before attempting to decode and map the response body.