diff --git a/server/routes/games.ts b/server/routes/games.ts
index 89496c1..d77429d 100755
--- a/server/routes/games.ts
+++ b/server/routes/games.ts
@@ -11,6 +11,8 @@ import basePath from '../basepath';
 import { getValidRoads, getValidCorners, isRuleEnabled } from '../util/validLocations.js';
 import { Player } from './games/types.js';
 import { normalizeIncoming, shuffleArray } from './games/utils.js';
+import type { GameState } from './games/state.js';
+import { serializeGame, deserializeGame, cloneGame } from './games/serialize.js';
 
 const router = express.Router();
 
diff --git a/server/routes/games/serialize.ts b/server/routes/games/serialize.ts
new file mode 100644
index 0000000..71c1b29
--- /dev/null
+++ b/server/routes/games/serialize.ts
@@ -0,0 +1,19 @@
+import type { GameState } from './state.js';
+
+export function serializeGame(game: GameState): string {
+  // Use a deterministic JSON serializer for snapshots; currently use JSON.stringify
+  return JSON.stringify(game);
+}
+
+export function deserializeGame(serialized: string): GameState {
+  try {
+    return JSON.parse(serialized) as GameState;
+  } catch (e) {
+    // If parsing fails, return a minimal empty game state to avoid crashes
+    return { players: [], placements: { corners: [], roads: [] } } as GameState;
+  }
+}
+
+export function cloneGame(game: GameState): GameState {
+  return deserializeGame(serializeGame(game));
+}
diff --git a/server/routes/games/state.ts b/server/routes/games/state.ts
new file mode 100644
index 0000000..a2c59cb
--- /dev/null
+++ b/server/routes/games/state.ts
@@ -0,0 +1,34 @@
+import { Player } from './types.js';
+
+export interface PlacementCorner {
+  color?: string | null;
+  type?: string | null; // settlement/city
+  data?: any;
+}
+
+export interface PlacementRoad {
+  color?: string | null;
+  data?: any;
+}
+
+export interface Placements {
+  corners: PlacementCorner[];
+  roads: PlacementRoad[];
+}
+
+export interface GameState {
+  id?: string | number;
+  name?: string;
+  players: Player[];
+  placements: Placements;
+  rules?: Record<string, any>;
+  state?: string;
+  robber?: number;
+  turn?: number;
+  history?: any[];
+  createdAt?: string;
+  [key: string]: any;
+}
+
+export type GameId = string | number;
+