diff --git a/packages/messaging/src/api.ts b/packages/messaging/src/api.ts
index 56af3928503..821c2fe759c 100644
--- a/packages/messaging/src/api.ts
+++ b/packages/messaging/src/api.ts
@@ -31,9 +31,11 @@ import {
 import { MessagingService } from './messaging-service';
 import { deleteToken as _deleteToken } from './api/deleteToken';
 import { getToken as _getToken } from './api/getToken';
+import { isSwSupported, isWindowSupported } from './api/isSupported';
 import { onBackgroundMessage as _onBackgroundMessage } from './api/onBackgroundMessage';
 import { onMessage as _onMessage } from './api/onMessage';
 import { _setDeliveryMetricsExportedToBigQueryEnabled } from './api/setDeliveryMetricsExportedToBigQueryEnabled';
+import { ERROR_FACTORY, ErrorCode } from './util/errors';
 
 /**
  * Retrieves a Firebase Cloud Messaging instance.
@@ -43,6 +45,22 @@ import { _setDeliveryMetricsExportedToBigQueryEnabled } from './api/setDeliveryM
  * @public
  */
 export function getMessagingInWindow(app: FirebaseApp = getApp()): Messaging {
+  // Conscious decision to make this async check non-blocking during the messaging instance
+  // initialization phase for performance consideration. An error would be thrown latter for
+  // developer's information. Developers can then choose to import and call `isSupported` for
+  // special handling.
+  isWindowSupported().then(
+    isSupported => {
+      // If `isWindowSupported()` resolved, but returned false.
+      if (!isSupported) {
+        throw ERROR_FACTORY.create(ErrorCode.UNSUPPORTED_BROWSER);
+      }
+    },
+    _ => {
+      // If `isWindowSupported()` rejected.
+      throw ERROR_FACTORY.create(ErrorCode.INDEXED_DB_UNSUPPORTED);
+    }
+  );
   return _getProvider(getModularInstance(app), 'messaging').getImmediate();
 }
 
@@ -54,10 +72,23 @@ export function getMessagingInWindow(app: FirebaseApp = getApp()): Messaging {
  * @public
  */
 export function getMessagingInSw(app: FirebaseApp = getApp()): Messaging {
-  return _getProvider(
-    getModularInstance(app),
-    'messaging-sw'
-  ).getImmediate();
+  // Conscious decision to make this async check non-blocking during the messaging instance
+  // initialization phase for performance consideration. An error would be thrown latter for
+  // developer's information. Developers can then choose to import and call `isSupported` for
+  // special handling.
+  isSwSupported().then(
+    isSupported => {
+      // If `isSwSupported()` resolved, but returned false.
+      if (!isSupported) {
+        throw ERROR_FACTORY.create(ErrorCode.UNSUPPORTED_BROWSER);
+      }
+    },
+    _ => {
+      // If `isSwSupported()` rejected.
+      throw ERROR_FACTORY.create(ErrorCode.INDEXED_DB_UNSUPPORTED);
+    }
+  );
+  return _getProvider(getModularInstance(app), 'messaging-sw').getImmediate();
 }
 
 /**
diff --git a/packages/messaging/src/helpers/register.ts b/packages/messaging/src/helpers/register.ts
index d85e0318e15..97c7dfb6327 100644
--- a/packages/messaging/src/helpers/register.ts
+++ b/packages/messaging/src/helpers/register.ts
@@ -21,8 +21,6 @@ import {
   ComponentType,
   InstanceFactory
 } from '@firebase/component';
-import { ERROR_FACTORY, ErrorCode } from '../util/errors';
-import { isSwSupported, isWindowSupported } from '../api/isSupported';
 import {
   onNotificationClick,
   onPush,
@@ -40,8 +38,6 @@ import { messageEventListener } from '../listeners/window-listener';
 const WindowMessagingFactory: InstanceFactory<'messaging'> = (
   container: ComponentContainer
 ) => {
-  maybeThrowWindowError();
-
   const messaging = new MessagingService(
     container.getProvider('app').getImmediate(),
     container.getProvider('installations-internal').getImmediate(),
@@ -58,8 +54,6 @@ const WindowMessagingFactory: InstanceFactory<'messaging'> = (
 const WindowMessagingInternalFactory: InstanceFactory<'messaging-internal'> = (
   container: ComponentContainer
 ) => {
-  maybeThrowWindowError();
-
   const messaging = container
     .getProvider('messaging')
     .getImmediate() as MessagingService;
@@ -71,40 +65,10 @@ const WindowMessagingInternalFactory: InstanceFactory<'messaging-internal'> = (
   return messagingInternal;
 };
 
-function maybeThrowWindowError(): void {
-  // Conscious decision to make this async check non-blocking during the messaging instance
-  // initialization phase for performance consideration. An error would be thrown latter for
-  // developer's information. Developers can then choose to import and call `isSupported` for
-  // special handling.
-  isWindowSupported()
-    .then(isSupported => {
-      if (!isSupported) {
-        throw ERROR_FACTORY.create(ErrorCode.UNSUPPORTED_BROWSER);
-      }
-    })
-    .catch(_ => {
-      throw ERROR_FACTORY.create(ErrorCode.INDEXED_DB_UNSUPPORTED);
-    });
-}
-
 declare const self: ServiceWorkerGlobalScope;
 const SwMessagingFactory: InstanceFactory<'messaging'> = (
   container: ComponentContainer
 ) => {
-  // Conscious decision to make this async check non-blocking during the messaging instance
-  // initialization phase for performance consideration. An error would be thrown latter for
-  // developer's information. Developers can then choose to import and call `isSupported` for
-  // special handling.
-  isSwSupported()
-    .then(isSupported => {
-      if (!isSupported) {
-        throw ERROR_FACTORY.create(ErrorCode.UNSUPPORTED_BROWSER);
-      }
-    })
-    .catch(_ => {
-      throw ERROR_FACTORY.create(ErrorCode.INDEXED_DB_UNSUPPORTED);
-    });
-
   const messaging = new MessagingService(
     container.getProvider('app').getImmediate(),
     container.getProvider('installations-internal').getImmediate(),