diff --git a/.github/workflows/api_game_domain.yaml b/.github/workflows/api_game_domain.yaml
new file mode 100644
index 000000000..c40c54918
--- /dev/null
+++ b/.github/workflows/api_game_domain.yaml
@@ -0,0 +1,20 @@
+name: api_game_domain
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+on:
+  pull_request:
+    paths:
+      - "api/packages/game_domain/**"
+      - ".github/workflows/api_game_domain.yaml"
+    branches:
+      - main
+
+jobs:
+  build:
+    uses: VeryGoodOpenSource/very_good_workflows/.github/workflows/dart_package.yml@v1
+    with:
+      dart_sdk: stable
+      working_directory: api/packages/game_domain
diff --git a/api/packages/game_domain/.gitignore b/api/packages/game_domain/.gitignore
new file mode 100644
index 000000000..526da1584
--- /dev/null
+++ b/api/packages/game_domain/.gitignore
@@ -0,0 +1,7 @@
+# See https://www.dartlang.org/guides/libraries/private-files
+
+# Files and directories created by pub
+.dart_tool/
+.packages
+build/
+pubspec.lock
\ No newline at end of file
diff --git a/api/packages/game_domain/analysis_options.yaml b/api/packages/game_domain/analysis_options.yaml
new file mode 100644
index 000000000..799268d3e
--- /dev/null
+++ b/api/packages/game_domain/analysis_options.yaml
@@ -0,0 +1 @@
+include: package:very_good_analysis/analysis_options.5.1.0.yaml
diff --git a/api/packages/game_domain/lib/game_domain.dart b/api/packages/game_domain/lib/game_domain.dart
new file mode 100644
index 000000000..8cd70b4a8
--- /dev/null
+++ b/api/packages/game_domain/lib/game_domain.dart
@@ -0,0 +1,4 @@
+/// Domain classes for the game.
+library game_domain;
+
+export 'src/models/models.dart';
diff --git a/api/packages/game_domain/lib/src/models/leaderboard_player.dart b/api/packages/game_domain/lib/src/models/leaderboard_player.dart
new file mode 100644
index 000000000..275485159
--- /dev/null
+++ b/api/packages/game_domain/lib/src/models/leaderboard_player.dart
@@ -0,0 +1,35 @@
+import 'package:equatable/equatable.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'leaderboard_player.g.dart';
+
+/// {@template leaderboard_player}
+/// A model that represents a player in the leaderboard.
+/// {@endtemplate}
+@JsonSerializable(ignoreUnannotated: true)
+class LeaderboardPlayer extends Equatable {
+  /// {@macro leaderboard_player}
+  const LeaderboardPlayer({
+    required this.id,
+    required this.initials,
+  });
+
+  /// {@macro leaderboard_player}
+  factory LeaderboardPlayer.fromJson(Map<String, dynamic> json) =>
+      _$LeaderboardPlayerFromJson(json);
+
+  /// Unique identifier of the leaderboard player object
+  /// and session id for the player.
+  @JsonKey()
+  final String id;
+
+  /// Initials of the player.
+  @JsonKey()
+  final String initials;
+
+  /// Returns a json representation from this instance.
+  Map<String, dynamic> toJson() => _$LeaderboardPlayerToJson(this);
+
+  @override
+  List<Object?> get props => [id, initials];
+}
diff --git a/api/packages/game_domain/lib/src/models/leaderboard_player.g.dart b/api/packages/game_domain/lib/src/models/leaderboard_player.g.dart
new file mode 100644
index 000000000..a9a747a2c
--- /dev/null
+++ b/api/packages/game_domain/lib/src/models/leaderboard_player.g.dart
@@ -0,0 +1,19 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'leaderboard_player.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+LeaderboardPlayer _$LeaderboardPlayerFromJson(Map<String, dynamic> json) =>
+    LeaderboardPlayer(
+      id: json['id'] as String,
+      initials: json['initials'] as String,
+    );
+
+Map<String, dynamic> _$LeaderboardPlayerToJson(LeaderboardPlayer instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'initials': instance.initials,
+    };
diff --git a/api/packages/game_domain/lib/src/models/models.dart b/api/packages/game_domain/lib/src/models/models.dart
new file mode 100644
index 000000000..4c1c38f2b
--- /dev/null
+++ b/api/packages/game_domain/lib/src/models/models.dart
@@ -0,0 +1 @@
+export 'leaderboard_player.dart';
diff --git a/api/packages/game_domain/pubspec.yaml b/api/packages/game_domain/pubspec.yaml
new file mode 100644
index 000000000..78f90dce0
--- /dev/null
+++ b/api/packages/game_domain/pubspec.yaml
@@ -0,0 +1,17 @@
+name: game_domain
+description: Domain classes for the game.
+version: 0.1.0+1
+publish_to: none
+
+environment:
+  sdk: ">=3.0.0 <4.0.0"
+
+dev_dependencies:
+  build_runner: ^2.4.8
+  mocktail: ^1.0.0
+  test: ^1.19.2
+  very_good_analysis: ^5.1.0
+
+dependencies:
+  equatable: ^2.0.5
+  json_annotation: ^4.8.1
\ No newline at end of file
diff --git a/api/packages/game_domain/test/src/models/leaderboard_player_test.dart b/api/packages/game_domain/test/src/models/leaderboard_player_test.dart
new file mode 100644
index 000000000..d091ea55d
--- /dev/null
+++ b/api/packages/game_domain/test/src/models/leaderboard_player_test.dart
@@ -0,0 +1,70 @@
+// ignore_for_file: prefer_const_constructors
+
+import 'package:game_domain/game_domain.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('LeaderboardPlayer', () {
+    test('can be instantiated', () {
+      expect(
+        LeaderboardPlayer(
+          id: 'id',
+          initials: 'TST',
+        ),
+        isNotNull,
+      );
+    });
+
+    final leaderboardPlayer = LeaderboardPlayer(
+      id: 'id',
+      initials: 'TST',
+    );
+
+    test('toJson returns the instance as json', () {
+      expect(
+        leaderboardPlayer.toJson(),
+        equals({
+          'id': 'id',
+          'initials': 'TST',
+        }),
+      );
+    });
+
+    test('fromJson returns the correct instance', () {
+      expect(
+        LeaderboardPlayer.fromJson(const {
+          'id': 'id',
+          'initials': 'TST',
+        }),
+        equals(leaderboardPlayer),
+      );
+    });
+
+    test('supports equality', () {
+      expect(
+        LeaderboardPlayer(id: '', initials: 'TST'),
+        equals(LeaderboardPlayer(id: '', initials: 'TST')),
+      );
+
+      expect(
+        LeaderboardPlayer(
+          id: '',
+          initials: 'TST',
+        ),
+        isNot(
+          equals(leaderboardPlayer),
+        ),
+      );
+
+      expect(
+        LeaderboardPlayer(
+          id: 'id',
+          initials: 'WOW',
+        ),
+        isNot(
+          equals(leaderboardPlayer),
+        ),
+      );
+    });
+  });
+}