diff --git a/src/backend/components/boardgame.tsx b/src/backend/components/boardgame.tsx
index ca46281..ef237c3 100644
--- a/src/backend/components/boardgame.tsx
+++ b/src/backend/components/boardgame.tsx
@@ -3,6 +3,7 @@ import {
   BoardgameStateType,
   CurrentOutcome,
   GameRules,
+  Player,
   SquareState,
   formatSquareState,
 } from "../../shared/datatypes.ts";
@@ -17,6 +18,12 @@ const getClassAndDisplayAttributes = (
   style: getDisplayStates(gameState, currentOutcome)[className] ? {} : { display: "none" },
 });
 
+const getSubmitAttributes = (key: string, targetState: BoardgameStateType) => ({
+  type: "submit" as const,
+  name: key,
+  value: targetState.serialize(),
+});
+
 const getCellHtml = ({
   key,
   gameState,
@@ -32,7 +39,7 @@ const getCellHtml = ({
 }) => {
   if (!gameState.board) {
     return (
-      <button type="submit" name={key} value={gameState.serialize()} disabled>
+      <button {...getSubmitAttributes(key, gameState)} disabled>
         {" "}
       </button>
     );
@@ -44,7 +51,7 @@ const getCellHtml = ({
       ? gameState.withMove(row, column)
       : gameState;
   return (
-    <button type="submit" name={key} value={nextGameState.serialize()} disabled={nextGameState === gameState}>
+    <button {...getSubmitAttributes(key, nextGameState)} disabled={nextGameState === gameState}>
       {formatSquareState(squareState)}
     </button>
   );
@@ -76,6 +83,34 @@ export const getBoardgameHtml = (key: string, gameState: BoardgameStateType, rul
           <span {...getClassAndDisplayAttributes("outcome-draw", gameState, currentOutcome)}>Draw</span>
         </p>
 
+        <p {...getClassAndDisplayAttributes("autoplayer-x-disabled", gameState, currentOutcome)}>
+          Currently X moves are made manually.{" "}
+          <button class="autoplayer-x-enable" {...getSubmitAttributes(key, gameState.withAutoPlayer(Player.X))}>
+            Make computer play for X.
+          </button>
+        </p>
+
+        <p {...getClassAndDisplayAttributes("autoplayer-x-enabled", gameState, currentOutcome)}>
+          Currently X moves are made by computer.{" "}
+          <button class="autoplayer-x-disable" {...getSubmitAttributes(key, gameState.withoutAutoPlayer(Player.X))}>
+            Make them manually.
+          </button>
+        </p>
+
+        <p {...getClassAndDisplayAttributes("autoplayer-o-disabled", gameState, currentOutcome)}>
+          Currently O moves are made manually.{" "}
+          <button class="autoplayer-o-enable" {...getSubmitAttributes(key, gameState.withAutoPlayer(Player.O))}>
+            Make computer play for O.
+          </button>
+        </p>
+
+        <p {...getClassAndDisplayAttributes("autoplayer-o-enabled", gameState, currentOutcome)}>
+          Currently O moves are made by computer.{" "}
+          <button class="autoplayer-o-disable" {...getSubmitAttributes(key, gameState.withoutAutoPlayer(Player.O))}>
+            Make them manually.
+          </button>
+        </p>
+
         <p>
           <button type="submit" name={key} value={gameState.withEmptyBoard().serialize()}>
             <span {...getClassAndDisplayAttributes("start-new-game", gameState, currentOutcome)}>Start game</span>
diff --git a/src/backend/main/boardgame-handler.ts b/src/backend/main/boardgame-handler.ts
index cfada31..52792f3 100644
--- a/src/backend/main/boardgame-handler.ts
+++ b/src/backend/main/boardgame-handler.ts
@@ -4,7 +4,7 @@ import { BoardgameState } from "../../shared/boardgame-state.ts";
 import { getBoardgameHtml } from "../components/boardgame.tsx";
 import { gamesRules } from "../../shared/rules.ts";
 import { getAllSolutions } from "../../shared/solver-cache.ts";
-import { CurrentOutcome, Player } from "../../shared/datatypes.ts";
+import { CurrentOutcome } from "../../shared/datatypes.ts";
 import { createOpponent } from "../../shared/opponent.ts";
 
 // Returns nothing if query parameter is uninitialized and a redirect was made,
@@ -21,7 +21,7 @@ export const handleBoardgame = (req: Request, res: Response, key: string) => {
     return;
   }
 
-  if (state.board && state.currentPlayer === Player.O) {
+  if (state.board && state.currentPlayer && state.autoPlayers.has(state.currentPlayer)) {
     const currentOutcome = rules.getBoardOutcome(state.board);
     if (currentOutcome === CurrentOutcome.Undecided) {
       const solutions = getAllSolutions(state.rows, state.columns, rules);
diff --git a/src/shared/array-utils.ts b/src/shared/array-utils.ts
index a0740e0..6e7af69 100644
--- a/src/shared/array-utils.ts
+++ b/src/shared/array-utils.ts
@@ -1,3 +1,7 @@
 export const repeat = <T>(value: T, size: number) => [...(new Array(size) as unknown[])].map(() => value);
 
 export const sequence = (size: number) => [...(new Array(size) as unknown[])].map((_, index) => index);
+
+const isNotEmpty = <T>(value: T): value is Exclude<T, null | undefined> => !!value;
+
+export const compact = <T>(array: T[]) => array.filter(isNotEmpty);
diff --git a/src/shared/boardgame-state.spec.ts b/src/shared/boardgame-state.spec.ts
index dc9acb5..b056cee 100644
--- a/src/shared/boardgame-state.spec.ts
+++ b/src/shared/boardgame-state.spec.ts
@@ -14,33 +14,57 @@ void t.test("Serialize / deserialize", async (t) => {
   void t.test("Empty state", async (t) => {
     t.equal(BoardgameState.fromSerialized(""), null);
     t.equal(BoardgameState.fromSerialized(null), null);
-    t.equal(BoardgameState.fromSerialized(".."), null);
+    t.equal(BoardgameState.fromSerialized("..."), null);
   });
 
   void t.test("1x1 state (incompletely serialized)", async (t) => {
     const state = BoardgameState.fromSerialized("1x1");
     t.ok(state);
-    t.equal(state?.serialize(), "1x1..");
+    t.equal(state?.serialize(), "1x1...");
     t.equal(state?.rows, 1);
     t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set());
     t.equal(state?.currentPlayer, null);
     t.equal(state?.currentPlayerName, "");
     t.equal(state?.board, null);
   });
 
   void t.test("1x1 state with empty board", async (t) => {
-    const state = createAndCheckBoardgameState(t, "1x1..");
+    const state = createAndCheckBoardgameState(t, "1x1...");
     t.equal(state?.rows, 1);
     t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set());
+    t.equal(state?.currentPlayer, null);
+    t.equal(state?.currentPlayerName, "");
+    t.equal(state?.board, null);
+  });
+
+  void t.test("1x1 state with empty board and one autoplayer", async (t) => {
+    const state = createAndCheckBoardgameState(t, "1x1.X..");
+    t.equal(state?.rows, 1);
+    t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set([Player.X]));
+    t.equal(state?.currentPlayer, null);
+    t.equal(state?.currentPlayerName, "");
+    t.equal(state?.board, null);
+  });
+
+  void t.test("1x1 state with empty board and one duplicated autoplayer", async (t) => {
+    const state = BoardgameState.fromSerialized("1x1.OOO..");
+    t.equal(state?.serialize(), "1x1.O..");
+    t.equal(state?.rows, 1);
+    t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set([Player.O]));
     t.equal(state?.currentPlayer, null);
     t.equal(state?.currentPlayerName, "");
     t.equal(state?.board, null);
   });
 
   void t.test("1x1 board with started game", async (t) => {
-    const state = createAndCheckBoardgameState(t, "1x1.X._");
+    const state = createAndCheckBoardgameState(t, "1x1..X._");
     t.equal(state?.rows, 1);
     t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set());
     t.equal(state?.currentPlayer, Player.X);
     t.equal(state?.currentPlayerName, "X");
     t.equal(state?.board?.hasRow(0), true);
@@ -51,9 +75,10 @@ void t.test("Serialize / deserialize", async (t) => {
   });
 
   void t.test("1x2 board with first move", async (t) => {
-    const state = createAndCheckBoardgameState(t, "1x2.O._X");
+    const state = createAndCheckBoardgameState(t, "1x2..O._X");
     t.equal(state?.rows, 1);
     t.equal(state?.columns, 2);
+    t.matchOnlyStrict(state?.autoPlayers, new Set());
     t.equal(state?.currentPlayer, Player.O);
     t.equal(state?.currentPlayerName, "O");
     t.equal(state?.board?.get(0, 0), SquareState.Unoccupied);
@@ -63,9 +88,10 @@ void t.test("Serialize / deserialize", async (t) => {
   });
 
   void t.test("2x1 board with first move", async (t) => {
-    const state = createAndCheckBoardgameState(t, "2x1.O._|X");
+    const state = createAndCheckBoardgameState(t, "2x1..O._|X");
     t.equal(state?.rows, 2);
     t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set());
     t.equal(state?.currentPlayer, Player.O);
     t.equal(state?.currentPlayerName, "O");
     t.equal(state?.board?.get(0, 0), SquareState.Unoccupied);
@@ -73,12 +99,37 @@ void t.test("Serialize / deserialize", async (t) => {
     t.equal(state?.board?.hasSquare(0, 1), false);
     t.equal(state?.board?.hasRow(2), false);
   });
+
+  void t.test("2x1 board with first move and two autoplayers", async (t) => {
+    const state = createAndCheckBoardgameState(t, "2x1.XO.O._|X");
+    t.equal(state?.rows, 2);
+    t.equal(state?.columns, 1);
+    t.matchOnlyStrict(state?.autoPlayers, new Set([Player.X, Player.O]));
+    t.equal(state?.currentPlayer, Player.O);
+    t.equal(state?.currentPlayerName, "O");
+    t.equal(state?.board?.get(0, 0), SquareState.Unoccupied);
+    t.equal(state?.board?.get(1, 0), SquareState.X);
+    t.equal(state?.board?.hasSquare(0, 1), false);
+    t.equal(state?.board?.hasRow(2), false);
+  });
+
+  void t.test("Error handling", async (t) => {
+    t.throws(() => BoardgameState.fromSerialized("0..."), {
+      message: "Incorrect dimensions",
+    });
+
+    {
+      const state = BoardgameState.fromSerialized("1x1.abc..");
+      t.equal(state?.serialize(), "1x1...");
+      t.matchOnlyStrict(state?.autoPlayers, new Set());
+    }
+  });
 });
 
 void t.test("Empty state creation", async (t) => {
   void t.test("0x0 board", async (t) => {
     const state = BoardgameState.createWithoutBoard(0, 0);
-    t.equal(state.serialize(), "0x0..");
+    t.equal(state.serialize(), "0x0...");
     t.equal(state.rows, 0);
     t.equal(state.columns, 0);
     t.equal(state.currentPlayer, null);
@@ -88,7 +139,7 @@ void t.test("Empty state creation", async (t) => {
 
   void t.test("1x0 board", async (t) => {
     const state = BoardgameState.createWithoutBoard(1, 0);
-    t.equal(state.serialize(), "1x0..");
+    t.equal(state.serialize(), "1x0...");
     t.equal(state.rows, 1);
     t.equal(state.columns, 0);
     t.equal(state.currentPlayer, null);
@@ -98,7 +149,7 @@ void t.test("Empty state creation", async (t) => {
 
   void t.test("1x1 board", async (t) => {
     const state = BoardgameState.createWithoutBoard(1, 1);
-    t.equal(state.serialize(), "1x1..");
+    t.equal(state.serialize(), "1x1...");
     t.equal(state.rows, 1);
     t.equal(state.columns, 1);
     t.equal(state.currentPlayer, null);
@@ -108,26 +159,20 @@ void t.test("Empty state creation", async (t) => {
 
   void t.test("1x2 board", async (t) => {
     const state = BoardgameState.createWithoutBoard(1, 2);
-    t.equal(state.serialize(), "1x2..");
+    t.equal(state.serialize(), "1x2...");
     t.equal(state.rows, 1);
     t.equal(state.columns, 2);
     t.equal(state.currentPlayer, null);
     t.equal(state.currentPlayerName, "");
     t.equal(state.board, null);
   });
-
-  void t.test("Error handling", async (t) => {
-    t.throws(() => BoardgameState.fromSerialized("0.."), {
-      message: "Incorrect dimensions",
-    });
-  });
 });
 
 void t.test("withEmptyBoard", async (t) => {
   void t.test("On 0x0 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "0x0..");
+    const oldState = createAndCheckBoardgameState(t, "0x0...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "0x0.X.");
+    t.equal(newState?.serialize(), "0x0..X.");
     t.equal(newState?.rows, 0);
     t.equal(newState?.columns, 0);
     t.equal(newState?.currentPlayer, Player.X);
@@ -136,9 +181,9 @@ void t.test("withEmptyBoard", async (t) => {
   });
 
   void t.test("On 0x1 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "0x1..");
+    const oldState = createAndCheckBoardgameState(t, "0x1...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "0x1.X.");
+    t.equal(newState?.serialize(), "0x1..X.");
     t.equal(newState?.rows, 0);
     t.equal(newState?.columns, 1);
     t.equal(newState?.currentPlayer, Player.X);
@@ -147,9 +192,9 @@ void t.test("withEmptyBoard", async (t) => {
   });
 
   void t.test("On 1x0 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "1x0..");
+    const oldState = createAndCheckBoardgameState(t, "1x0...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "1x0.X.");
+    t.equal(newState?.serialize(), "1x0..X.");
     t.equal(newState?.rows, 1);
     t.equal(newState?.columns, 0);
     t.equal(newState?.currentPlayer, Player.X);
@@ -158,9 +203,9 @@ void t.test("withEmptyBoard", async (t) => {
   });
 
   void t.test("On 1x1 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "1x1..");
+    const oldState = createAndCheckBoardgameState(t, "1x1...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "1x1.X._");
+    t.equal(newState?.serialize(), "1x1..X._");
     t.equal(newState?.rows, 1);
     t.equal(newState?.columns, 1);
     t.equal(newState?.currentPlayer, Player.X);
@@ -169,9 +214,9 @@ void t.test("withEmptyBoard", async (t) => {
   });
 
   void t.test("On 1x2 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "1x2..");
+    const oldState = createAndCheckBoardgameState(t, "1x2...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "1x2.X.__");
+    t.equal(newState?.serialize(), "1x2..X.__");
     t.equal(newState?.rows, 1);
     t.equal(newState?.columns, 2);
     t.equal(newState?.currentPlayer, Player.X);
@@ -180,9 +225,9 @@ void t.test("withEmptyBoard", async (t) => {
   });
 
   void t.test("On 2x1 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "2x1..");
+    const oldState = createAndCheckBoardgameState(t, "2x1...");
     const newState = oldState?.withEmptyBoard();
-    t.equal(newState?.serialize(), "2x1.X._|_");
+    t.equal(newState?.serialize(), "2x1..X._|_");
     t.equal(newState?.rows, 2);
     t.equal(newState?.columns, 1);
     t.equal(newState?.currentPlayer, Player.X);
@@ -191,12 +236,95 @@ void t.test("withEmptyBoard", async (t) => {
   });
 });
 
+void t.test("withAutoPlayer", async (t) => {
+  void t.test("On uninitialized board", async (t) => {
+    const oldState = createAndCheckBoardgameState(t, "2x3...");
+
+    const newStateX = oldState?.withAutoPlayer(Player.X);
+    t.equal(newStateX?.serialize(), "2x3.X..");
+    t.matchOnlyStrict(newStateX?.autoPlayers, new Set([Player.X]));
+
+    const newStateO = oldState?.withAutoPlayer(Player.O);
+    t.equal(newStateO?.serialize(), "2x3.O..");
+    t.matchOnlyStrict(newStateO?.autoPlayers, new Set([Player.O]));
+
+    const newStateXO = newStateX?.withAutoPlayer(Player.O);
+    t.equal(newStateXO?.serialize(), "2x3.XO..");
+    t.matchOnlyStrict(newStateXO?.autoPlayers, new Set([Player.X, Player.O]));
+
+    const newStateOO = newStateO?.withAutoPlayer(Player.O);
+    t.equal(newStateOO?.serialize(), "2x3.O..");
+    t.matchOnlyStrict(newStateOO?.autoPlayers, new Set([Player.O]));
+  });
+  void t.test("On 2x3 board", async (t) => {
+    const oldState = createAndCheckBoardgameState(t, "2x3..X.__X|O__");
+
+    const newStateX = oldState?.withAutoPlayer(Player.X);
+    t.equal(newStateX?.serialize(), "2x3.X.X.__X|O__");
+    t.matchOnlyStrict(newStateX?.autoPlayers, new Set([Player.X]));
+
+    const newStateO = oldState?.withAutoPlayer(Player.O);
+    t.equal(newStateO?.serialize(), "2x3.O.X.__X|O__");
+    t.matchOnlyStrict(newStateO?.autoPlayers, new Set([Player.O]));
+
+    const newStateXO = newStateX?.withAutoPlayer(Player.O);
+    t.equal(newStateXO?.serialize(), "2x3.XO.X.__X|O__");
+    t.matchOnlyStrict(newStateXO?.autoPlayers, new Set([Player.X, Player.O]));
+
+    const newStateOO = newStateO?.withAutoPlayer(Player.O);
+    t.equal(newStateOO?.serialize(), "2x3.O.X.__X|O__");
+    t.matchOnlyStrict(newStateOO?.autoPlayers, new Set([Player.O]));
+  });
+});
+
+void t.test("withoutAutoPlayer", async (t) => {
+  void t.test("On uninitialized board", async (t) => {
+    const oldState = createAndCheckBoardgameState(t, "2x3.XO..");
+
+    const newStateX = oldState?.withoutAutoPlayer(Player.O);
+    t.equal(newStateX?.serialize(), "2x3.X..");
+    t.matchOnlyStrict(newStateX?.autoPlayers, new Set([Player.X]));
+
+    const newStateO = oldState?.withoutAutoPlayer(Player.X);
+    t.equal(newStateO?.serialize(), "2x3.O..");
+    t.matchOnlyStrict(newStateO?.autoPlayers, new Set([Player.O]));
+
+    const newStateNone = newStateX?.withoutAutoPlayer(Player.X);
+    t.equal(newStateNone?.serialize(), "2x3...");
+    t.matchOnlyStrict(newStateNone?.autoPlayers, new Set());
+
+    const newStateOO = newStateO?.withoutAutoPlayer(Player.X);
+    t.equal(newStateOO?.serialize(), "2x3.O..");
+    t.matchOnlyStrict(newStateOO?.autoPlayers, new Set([Player.O]));
+  });
+
+  void t.test("On 2x3 board", async (t) => {
+    const oldState = createAndCheckBoardgameState(t, "2x3.XO.X.__X|O__");
+
+    const newStateX = oldState?.withoutAutoPlayer(Player.O);
+    t.equal(newStateX?.serialize(), "2x3.X.X.__X|O__");
+    t.matchOnlyStrict(newStateX?.autoPlayers, new Set([Player.X]));
+
+    const newStateO = oldState?.withoutAutoPlayer(Player.X);
+    t.equal(newStateO?.serialize(), "2x3.O.X.__X|O__");
+    t.matchOnlyStrict(newStateO?.autoPlayers, new Set([Player.O]));
+
+    const newStateNone = newStateX?.withoutAutoPlayer(Player.X);
+    t.equal(newStateNone?.serialize(), "2x3..X.__X|O__");
+    t.matchOnlyStrict(newStateNone?.autoPlayers, new Set());
+
+    const newStateOO = newStateO?.withoutAutoPlayer(Player.X);
+    t.equal(newStateOO?.serialize(), "2x3.O.X.__X|O__");
+    t.matchOnlyStrict(newStateOO?.autoPlayers, new Set([Player.O]));
+  });
+});
+
 void t.test("withMove", async (t) => {
   void t.test("On 2x3 board", async (t) => {
-    const oldState = createAndCheckBoardgameState(t, "2x3.X.___|___");
+    const oldState = createAndCheckBoardgameState(t, "2x3..X.___|___");
 
     const firstMoveState = oldState?.withMove(0, 1);
-    t.equal(firstMoveState?.serialize(), "2x3.O._X_|___");
+    t.equal(firstMoveState?.serialize(), "2x3..O._X_|___");
     t.equal(firstMoveState?.rows, 2);
     t.equal(firstMoveState?.columns, 3);
     t.equal(firstMoveState?.currentPlayer, Player.O);
@@ -204,7 +332,7 @@ void t.test("withMove", async (t) => {
     t.equal(firstMoveState?.board?.serialize(), "_X_|___");
 
     const secondMoveState = firstMoveState?.withMove(1, 2);
-    t.equal(secondMoveState?.serialize(), "2x3.X._X_|__O");
+    t.equal(secondMoveState?.serialize(), "2x3..X._X_|__O");
     t.equal(secondMoveState?.rows, 2);
     t.equal(secondMoveState?.columns, 3);
     t.equal(secondMoveState?.currentPlayer, Player.X);
@@ -213,7 +341,7 @@ void t.test("withMove", async (t) => {
   });
 
   void t.test("Error handling", async () => {
-    const unstartedBoard = createAndCheckBoardgameState(t, "1x1..");
+    const unstartedBoard = createAndCheckBoardgameState(t, "1x1...");
     t.throws(() => unstartedBoard?.withMove(0, 0), {
       message: "Game is not started",
     });
@@ -222,17 +350,17 @@ void t.test("withMove", async (t) => {
 
 void t.test("Sample usage scenario", async (t) => {
   const noBoardState = BoardgameState.createWithoutBoard(2, 3);
-  t.equal(noBoardState.serialize(), "2x3..");
+  t.equal(noBoardState.serialize(), "2x3...");
 
   const gameStartedState = noBoardState.withEmptyBoard();
-  t.equal(gameStartedState.serialize(), "2x3.X.___|___");
+  t.equal(gameStartedState.serialize(), "2x3..X.___|___");
 
   const firstMoveState = gameStartedState.withMove(0, 1);
-  t.equal(firstMoveState.serialize(), "2x3.O._X_|___");
+  t.equal(firstMoveState.serialize(), "2x3..O._X_|___");
 
   const secondMoveState = firstMoveState.withMove(1, 2);
-  t.equal(secondMoveState.serialize(), "2x3.X._X_|__O");
+  t.equal(secondMoveState.serialize(), "2x3..X._X_|__O");
 
   const thirdMoveState = secondMoveState.withMove(1, 0);
-  t.equal(thirdMoveState.serialize(), "2x3.O._X_|X_O");
+  t.equal(thirdMoveState.serialize(), "2x3..O._X_|X_O");
 });
diff --git a/src/shared/boardgame-state.ts b/src/shared/boardgame-state.ts
index 61012ed..13c5553 100644
--- a/src/shared/boardgame-state.ts
+++ b/src/shared/boardgame-state.ts
@@ -1,3 +1,4 @@
+import { compact } from "./array-utils.ts";
 import { Board } from "./board.ts";
 import {
   BoardType,
@@ -25,6 +26,16 @@ const parseDimensions = (dimensionsSerialized: string | undefined) => {
   return [parseInt(rowsSerialized, 10), parseInt(columnsSerialized, 10)] as const;
 };
 
+const parsePlayers = (playersSerialized: string | undefined) => {
+  if (!playersSerialized) {
+    return new Set<Player>();
+  }
+
+  return new Set(compact(playersSerialized.split("").map(parsePlayer)));
+};
+
+const serializePlayers = (players: ReadonlySet<Player>) => [...players].map(formatPlayer).join("");
+
 const parseBoard = (boardSerialized: string | undefined) => {
   if (!boardSerialized) {
     return null;
@@ -45,6 +56,7 @@ export class BoardgameState implements BoardgameStateType {
   constructor(
     readonly rows: number,
     readonly columns: number,
+    readonly autoPlayers: ReadonlySet<Player>,
     readonly currentPlayer: Player | null,
     readonly board: BoardType | null,
   ) {}
@@ -54,11 +66,29 @@ export class BoardgameState implements BoardgameStateType {
   }
 
   static createWithoutBoard(rows: number, columns: number) {
-    return new BoardgameState(rows, columns, null, null);
+    return new BoardgameState(rows, columns, new Set<Player>(), null, null);
   }
 
   withEmptyBoard() {
-    return new BoardgameState(this.rows, this.columns, FIRST_PLAYER, Board.createEmpty(this.rows, this.columns));
+    return new BoardgameState(
+      this.rows,
+      this.columns,
+      this.autoPlayers,
+      FIRST_PLAYER,
+      Board.createEmpty(this.rows, this.columns),
+    );
+  }
+
+  withAutoPlayer(player: Player) {
+    const autoPlayers = new Set(this.autoPlayers);
+    autoPlayers.add(player);
+    return new BoardgameState(this.rows, this.columns, autoPlayers, this.currentPlayer, this.board);
+  }
+
+  withoutAutoPlayer(player: Player) {
+    const autoPlayers = new Set(this.autoPlayers);
+    autoPlayers.delete(player);
+    return new BoardgameState(this.rows, this.columns, autoPlayers, this.currentPlayer, this.board);
   }
 
   withMove(row: number, column: number) {
@@ -68,11 +98,13 @@ export class BoardgameState implements BoardgameStateType {
 
     const nextBoard = this.board.with(row, column, getOccupiedStateByPlayer(this.currentPlayer));
     const nextPlayer = getNextPlayer(this.currentPlayer);
-    return new BoardgameState(this.rows, this.columns, nextPlayer, nextBoard);
+    return new BoardgameState(this.rows, this.columns, this.autoPlayers, nextPlayer, nextBoard);
   }
 
   static fromSerialized(serialized: string | null) {
-    const [dimensionsSerialized, currentPlayerSerialized, boardSerialized] = (serialized ?? "").split(".");
+    const [dimensionsSerialized, autoPlayersSerialized, currentPlayerSerialized, boardSerialized] = (
+      serialized ?? ""
+    ).split(".");
 
     const dimensions = parseDimensions(dimensionsSerialized);
     if (!dimensions) {
@@ -80,13 +112,14 @@ export class BoardgameState implements BoardgameStateType {
     }
 
     const [rows, columns] = dimensions;
+    const autoPlayers = parsePlayers(autoPlayersSerialized);
     const currentPlayer = currentPlayerSerialized ? parsePlayer(currentPlayerSerialized) : null;
     const board = parseBoard(boardSerialized);
 
-    return new BoardgameState(rows, columns, currentPlayer, board);
+    return new BoardgameState(rows, columns, autoPlayers, currentPlayer, board);
   }
 
   serialize() {
-    return `${this.rows}x${this.columns}.${this.currentPlayerName}.${serializeBoard(this.board)}`;
+    return `${this.rows}x${this.columns}.${serializePlayers(this.autoPlayers)}.${this.currentPlayerName}.${serializeBoard(this.board)}`;
   }
 }
diff --git a/src/shared/datatypes.ts b/src/shared/datatypes.ts
index c6ee123..78120d2 100644
--- a/src/shared/datatypes.ts
+++ b/src/shared/datatypes.ts
@@ -42,12 +42,15 @@ export type ExpectedOutcome = {
 export type BoardgameStateType = {
   readonly rows: number;
   readonly columns: number;
+  readonly autoPlayers: ReadonlySet<Player>;
   readonly currentPlayer: Player | null;
   readonly board: BoardType | null;
 
   readonly currentPlayerName: string;
 
   withEmptyBoard(): BoardgameStateType;
+  withAutoPlayer(player: Player): BoardgameStateType;
+  withoutAutoPlayer(player: Player): BoardgameStateType;
   withMove(row: number, column: number): BoardgameStateType;
   serialize(): string;
 };
diff --git a/src/shared/display.ts b/src/shared/display.ts
index 0a08d3e..c8e78a5 100644
--- a/src/shared/display.ts
+++ b/src/shared/display.ts
@@ -1,9 +1,13 @@
-import { BoardgameStateType, CurrentOutcome } from "./datatypes.ts";
+import { BoardgameStateType, CurrentOutcome, Player } from "./datatypes.ts";
 
 export const getDisplayStates = (gameState: BoardgameStateType, currentOutcome: CurrentOutcome) => ({
   "outcome-winx": currentOutcome === CurrentOutcome.WinX,
   "outcome-wino": currentOutcome === CurrentOutcome.WinO,
   "outcome-draw": currentOutcome === CurrentOutcome.Draw,
+  "autoplayer-x-enabled": gameState.autoPlayers.has(Player.X),
+  "autoplayer-x-disabled": !gameState.autoPlayers.has(Player.X),
+  "autoplayer-o-enabled": gameState.autoPlayers.has(Player.O),
+  "autoplayer-o-disabled": !gameState.autoPlayers.has(Player.O),
   "start-new-game": !gameState.board,
   "start-clear-game": gameState.board,
 });