flutter-implement-json-serialization

Use dart:convert's jsonDecode to parse the response body, cast the result to Map<String, dynamic>, and pass it to a fromJson factory constructor on your model class. Implement a toJson method to serialize the model back to a Map for encoding with jsonEncode.

Use Flutter's compute() function to run parsing in a background isolate. Define a top-level parsing function that decodes the response body and maps it to your models, then call compute(parseFunction, response.body) after receiving the HTTP response.

Manual serialization with dart:convert fits simple data structures with few models where you want full control over mapping logic. For large projects with many nested models, code generation with json_serializable reduces boilerplate and maintenance effort.

jsonDecode returns dynamic, so accessing fields without casting causes runtime type errors. Always cast the result explicitly to Map<String, dynamic> for objects or List<dynamic> for arrays, and use pattern matching in fromJson to enforce expected types.

No, throw an Exception when the response status code is not successful, such as anything other than 200 or 201. Returning null hides failures and pushes error handling onto callers, while exceptions make failures explicit and catchable.