All 7 JSON Serialization & Deserialization questions
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How do you properly convert a decoded JSON Map into a genuinely strongly typed custom Dart model class, rather than continuing to work directly with a considerably less safe raw dynamic Map throughout your entire app? How does the json_serializable package let you automatically generate the required fromJson and toJson methods for your own Dart model classes, avoiding needing to write that particular repetitive boilerplate code entirely completely by hand yourself? How should you properly handle a genuinely nullable or optional field within your JSON deserialization logic, ensuring your app genuinely does not crash if a specific expected field happens to actually be missing from a given received response? How do you properly handle deserializing a genuinely nested JSON structure, such as an order object that itself contains an embedded nested list of individual line item objects, into a properly correctly structured set of nested Dart model classes? How can you properly implement genuinely custom JSON converters specifically for a given specific type that json_serializable does not already directly know exactly how to properly handle by default, such as converting a DateTime value to and from a specific particular custom string format? What are the practical performance considerations of parsing a genuinely very large JSON response, and how does moving that particular parsing work onto a genuinely separate isolate help meaningfully avoid causing your app's own visible interface to freeze?
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What is JSON serialization and deserialization, and how do Dart's own built in jsonEncode and jsonDecode functions let you convert genuinely freely between a Dart object and its own corresponding JSON text representation?

Beginner

Answer

Serialization means converting a genuine Dart object into a JSON formatted text string, typically specifically to actually send that data over a network or properly save it to a local file, while deserialization means the exact reverse genuine process, converting a JSON formatted text string back into a genuinely usable Dart object, and Dart's own built in dart:convert library provides jsonEncode specifically for serialization and jsonDecode specifically for deserialization, both working directly with Dart's own basic native Map and List types representing that particular underlying JSON structure.
final jsonString = jsonEncode({'name': 'Alex', 'age': 30});
final decoded = jsonDecode(jsonString);
print(decoded['name']);
Real-world example A weather app converts its own fetched weather data directly into a JSON string using jsonEncode specifically to properly cache it locally, then later properly converts that exact same cached JSON string back into a genuinely usable Dart Map using jsonDecode when the app is later actually genuinely reopened.

Common follow-ups: What is the specific practical difference between jsonEncode and jsonDecode in terms of exactly what direction each one actually converts data?;What genuinely happens if you try to actually decode a JSON string that is genuinely malformed or invalid?

Dart Collections & Generics;Networking with HTTP & Dio
All 7 JSON Serialization & Deserialization questions