diff --git a/src/client/HostLobbyModal.ts b/src/client/HostLobbyModal.ts
index be9eb3806..c80b8c4f8 100644
--- a/src/client/HostLobbyModal.ts
+++ b/src/client/HostLobbyModal.ts
@@ -1011,21 +1011,12 @@ export class HostLobbyModal extends BaseModal {
     // If the modal closes as part of starting the game, do not leave the lobby
     this.leaveLobbyOnClose = false;
 
-    const config = await getRuntimeClientServerConfig();
-    const response = await fetch(
-      `${window.location.origin}/${config.workerPath(this.lobbyId)}/api/start_game/${this.lobbyId}`,
-      {
-        method: "POST",
-        headers: {
-          "Content-Type": "application/json",
-        },
-      },
+    this.dispatchEvent(
+      new CustomEvent("start-game", {
+        bubbles: true,
+        composed: true,
+      }),
     );
-
-    if (!response.ok) {
-      this.leaveLobbyOnClose = true;
-    }
-    return response;
   }
 
   private kickPlayer(clientID: string) {
diff --git a/src/client/Main.ts b/src/client/Main.ts
index 93dfc47df..2f418c030 100644
--- a/src/client/Main.ts
+++ b/src/client/Main.ts
@@ -51,6 +51,7 @@ import { TerritoryPatternsModal } from "./TerritoryPatternsModal";
 import { TokenLoginModal } from "./TokenLoginModal";
 import {
   SendKickPlayerIntentEvent,
+  SendStartGameEvent,
   SendUpdateGameConfigIntentEvent,
 } from "./Transport";
 import { UserSettingModal } from "./UserSettingModal";
@@ -215,6 +216,7 @@ declare global {
   interface DocumentEventMap {
     "join-lobby": CustomEvent<JoinLobbyEvent>;
     "kick-player": CustomEvent;
+    "start-game": CustomEvent;
     "join-changed": CustomEvent;
     "open-matchmaking": CustomEvent<undefined>;
   }
@@ -311,6 +313,7 @@ class Client {
     document.addEventListener("join-lobby", this.handleJoinLobby.bind(this));
     document.addEventListener("leave-lobby", this.handleLeaveLobby.bind(this));
     document.addEventListener("kick-player", this.handleKickPlayer.bind(this));
+    document.addEventListener("start-game", this.handleStartGame.bind(this));
     document.addEventListener(
       "update-game-config",
       this.handleUpdateGameConfig.bind(this),
@@ -932,6 +935,12 @@ class Client {
     }
   }
 
+  private handleStartGame() {
+    if (this.eventBus) {
+      this.eventBus.emit(new SendStartGameEvent());
+    }
+  }
+
   private handleUpdateGameConfig(event: CustomEvent) {
     const { config } = event.detail;
 
diff --git a/src/client/Transport.ts b/src/client/Transport.ts
index 2fac031d0..1e4526a8c 100644
--- a/src/client/Transport.ts
+++ b/src/client/Transport.ts
@@ -173,6 +173,8 @@ export class SendUpdateGameConfigIntentEvent implements GameEvent {
   constructor(public readonly config: Partial<GameConfig>) {}
 }
 
+export class SendStartGameEvent implements GameEvent {}
+
 export class Transport {
   private socket: WebSocket | null = null;
 
@@ -262,6 +264,8 @@ export class Transport {
     this.eventBus.on(SendUpdateGameConfigIntentEvent, (e) =>
       this.onSendUpdateGameConfigIntent(e),
     );
+
+    this.eventBus.on(SendStartGameEvent, () => this.onSendStartGame());
   }
 
   private startPing() {
@@ -644,6 +648,10 @@ export class Transport {
     });
   }
 
+  private onSendStartGame() {
+    this.sendIntent({ type: "start_game" });
+  }
+
   private sendIntent(intent: Intent) {
     if (this.isLocal || this.socket?.readyState === WebSocket.OPEN) {
       const msg = {
diff --git a/src/core/Schemas.ts b/src/core/Schemas.ts
index 870dcff55..4a1636e19 100644
--- a/src/core/Schemas.ts
+++ b/src/core/Schemas.ts
@@ -50,7 +50,8 @@ export type Intent =
   | DeleteUnitIntent
   | KickPlayerIntent
   | TogglePauseIntent
-  | UpdateGameConfigIntent;
+  | UpdateGameConfigIntent
+  | StartGameIntent;
 
 export type AttackIntent = z.infer<typeof AttackIntentSchema>;
 export type CancelAttackIntent = z.infer<typeof CancelAttackIntentSchema>;
@@ -84,6 +85,7 @@ export type TogglePauseIntent = z.infer<typeof TogglePauseIntentSchema>;
 export type UpdateGameConfigIntent = z.infer<
   typeof UpdateGameConfigIntentSchema
 >;
+export type StartGameIntent = z.infer<typeof StartGameIntentSchema>;
 
 export type Turn = z.infer<typeof TurnSchema>;
 export type GameConfig = z.infer<typeof GameConfigSchema>;
@@ -453,6 +455,10 @@ export const UpdateGameConfigIntentSchema = z.object({
   config: GameConfigSchema.partial(),
 });
 
+export const StartGameIntentSchema = z.object({
+  type: z.literal("start_game"),
+});
+
 const IntentSchema = z.discriminatedUnion("type", [
   AttackIntentSchema,
   CancelAttackIntentSchema,
@@ -478,6 +484,7 @@ const IntentSchema = z.discriminatedUnion("type", [
   KickPlayerIntentSchema,
   TogglePauseIntentSchema,
   UpdateGameConfigIntentSchema,
+  StartGameIntentSchema,
 ]);
 
 // StampedIntent = Intent with server-stamped clientID (used in turns and execution)
diff --git a/src/server/GameServer.ts b/src/server/GameServer.ts
index ab95da102..2f6175776 100644
--- a/src/server/GameServer.ts
+++ b/src/server/GameServer.ts
@@ -487,6 +487,35 @@ export class GameServer {
                 this.updateGameConfig(stampedIntent.config);
                 return;
               }
+              case "start_game": {
+                if (client.clientID !== this.lobbyCreatorID) {
+                  this.log.warn(`Only lobby creator can start game`, {
+                    clientID: client.clientID,
+                    creatorID: this.lobbyCreatorID,
+                    gameID: this.id,
+                  });
+                  return;
+                }
+                if (this.isPublic()) {
+                  this.log.warn(`Cannot start public game via WebSocket`, {
+                    gameID: this.id,
+                  });
+                  return;
+                }
+                if (this.hasStarted()) {
+                  this.log.warn(`Cannot start game that has already started`, {
+                    gameID: this.id,
+                    clientID: client.clientID,
+                  });
+                  return;
+                }
+                this.log.info(`Lobby creator starting game via WebSocket`, {
+                  creatorID: client.clientID,
+                  gameID: this.id,
+                });
+                this.start();
+                return;
+              }
               case "toggle_pause": {
                 // Only lobby creator can pause/resume
                 if (client.clientID !== this.lobbyCreatorID) {
diff --git a/src/server/Worker.ts b/src/server/Worker.ts
index b775d393a..2c6b36d63 100644
--- a/src/server/Worker.ts
+++ b/src/server/Worker.ts
@@ -210,25 +210,6 @@ export async function startWorker() {
     res.json(game.gameInfo());
   });
 
-  // Add other endpoints from your original server
-  app.post("/api/start_game/:id", async (req, res) => {
-    log.info(`starting private lobby with id ${req.params.id}`);
-    const game = gm.game(req.params.id);
-    if (!game) {
-      return;
-    }
-    if (game.isPublic()) {
-      // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
-      const clientIP = req.ip || req.socket.remoteAddress || "unknown";
-      log.info(
-        `cannot start public game ${game.id}, game is public, ip: ${ipAnonymize(clientIP)}`,
-      );
-      return;
-    }
-    game.start();
-    res.status(200).json({ success: true });
-  });
-
   app.get("/api/game/:id/exists", async (req, res) => {
     const lobbyId = req.params.id;
     res.json({