diff --git a/pxtlib/emitter/cloud.ts b/pxtlib/emitter/cloud.ts
index 69bc9cdf60eb..29e9ec1d2a9a 100644
--- a/pxtlib/emitter/cloud.ts
+++ b/pxtlib/emitter/cloud.ts
@@ -125,6 +125,16 @@ namespace pxt.Cloud {
         })
     }
 
+    export async function downloadBuiltSimJsInfoAsync(id: string): Promise<pxtc.BuiltSimJsInfo> {
+        const targetVersion = pxt.appTarget.versions && pxt.appTarget.versions.target || "";
+        const url = pxt.U.stringifyQueryString(id + "/js", { v: "v" + targetVersion }) + (id.startsWith("S") ? `&time=${Date.now()}` : "");
+        const resp = await privateRequestAsync({
+            url,
+            forceLiveEndpoint: true,
+        });
+        return resp.json;
+    }
+
     export async function markdownAsync(docid: string, locale?: string, propagateExceptions?: boolean): Promise<string> {
         // 1h check on markdown content if not on development server
         const MARKDOWN_EXPIRATION = pxt.BrowserUtils.isLocalHostDev() ? 0 : 1 * 60 * 60 * 1000;
diff --git a/pxtrunner/runner.ts b/pxtrunner/runner.ts
index 7bb57b15a349..d9f56c031e15 100644
--- a/pxtrunner/runner.ts
+++ b/pxtrunner/runner.ts
@@ -375,7 +375,7 @@ namespace pxt.runner {
     }
 
     export async function simulateAsync(container: HTMLElement, simOptions: SimulateOptions): Promise<pxtc.BuiltSimJsInfo> {
-        const builtSimJS = simOptions.builtJsInfo || await buildSimJsInfo(simOptions);
+        const builtSimJS = simOptions.builtJsInfo || await fetchSimJsInfo(simOptions) || await buildSimJsInfo(simOptions);
         const { js } = builtSimJS;
 
         if (!js) {
@@ -466,6 +466,16 @@ namespace pxt.runner {
         simDriver?.postMessage(msg);
     }
 
+    export async function fetchSimJsInfo(simOptions: SimulateOptions): Promise<pxtc.BuiltSimJsInfo> {
+        try {
+            return await pxt.Cloud.downloadBuiltSimJsInfoAsync(simOptions.id);
+        } catch (e) {
+            // This exception will happen in the majority of cases, so we don't want to log it unless for debugging.
+            pxt.debug(e.toString());
+            return undefined;
+        }
+    }
+
     export async function buildSimJsInfo(simOptions: SimulateOptions): Promise<pxtc.BuiltSimJsInfo> {
         await loadPackageAsync(simOptions.id, simOptions.code, simOptions.dependencies);