version MIT License PRs Welcome

flutterfire_json_converters package supplies some useful json_converters when you use json_serializable or freezed for your FlutterFire apps.

How to use


This package uses Dart 3 features, so you need to use compatible Dart (Flutter) SDK.

  sdk: '>=3.0.0 <4.0.0'
  flutter: '>=3.10.0'


In order to use flutterfire_json_converters with json_serializable or freezed, you need to install the following packages.

# For code generation
flutter pub add --dev build_runner

# If you use freezed
flutter pub add freezed_annotation
flutter pub add --dev freezed

# if you use json_serializable
flutter pub add json_serializable
flutter pub add json_annotation
flutter pub add --dev json_serializable


When dealing with Cloud Firestore's Timestamp field, you may encounter the following scenarios:

  • You want to manipulate the field as a Dart DateTime type.
  • During the creation or updating of Cloud Firestore documents, you may want to automatically set certain fields (e.g., updatedAt) to FieldValue.serverTimestamp().
  • For other fields (e.g., createdAt), you might sometimes prefer to specify a client-side DateTime and save it to a Cloud Firestore document, while at other times you might want to automatically set it to FieldValue.serverTimestamp().

For such scenarios, you can define DateTime/Timestamp fields as SealedTimestamp type with @sealedTimestampConverter/@alwaysUseServerTimestampSealedTimestampConverter json_converter annotations like below:

class Entity {
    required this.name,
    this.createdAt = const ServerTimestamp(),
    this.updatedAt = const ServerTimestamp(),

  factory Entity.fromJson(Map<String, dynamic> json) => _$EntityFromJson(json);

  final String name;

  // Handle both Dart's `DateTime` and Cloud Firestore's `Timestamp` types.
  final SealedTimestamp createdAt;

  // Handle both Dart's `DateTime` and Cloud Firestore's `Timestamp` types, and
  // always use `FieldValue.serverTimestamp()` when creating/updating a document.
  final SealedTimestamp updatedAt;

  Map<String, dynamic> toJson() => _$EntityToJson(this);

When you want to get DateTime value of their fields on Dart client-side, you can call SealedTimestamp.dateTime.

final epoch = DateTime(1970);
final entity = Entity(name: 'foo', createdAt: ClientDateTime(epoch));

print(entity.name); // 'foo'
print(entity.createdAt.dateTime) // 1970-01-01 00:00:00.000
print(entity.updatedAt.dateTime) // null

final json = entity.toJson();

print(json['name']); // 'foo'
print(json['createdAt']); // Timestamp(seconds=0, nanoseconds=0)
print(json['updatedAt']); // FieldValue(Instance of 'MethodChannelFieldValue')


This package is developed with reference to:


We would like to express our gratitude for their valuable contributions.