diff --git a/.changeset/move-extension-factory-middleware-app-api.md b/.changeset/move-extension-factory-middleware-app-api.md
new file mode 100644
index 0000000000..6cc77a5d26
--- /dev/null
+++ b/.changeset/move-extension-factory-middleware-app-api.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-app-api': patch
+---
+
+Added the `ExtensionFactoryMiddleware` type as a public export.
diff --git a/.changeset/move-extension-factory-middleware-plugin-api.md b/.changeset/move-extension-factory-middleware-plugin-api.md
new file mode 100644
index 0000000000..607da295a3
--- /dev/null
+++ b/.changeset/move-extension-factory-middleware-plugin-api.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-plugin-api': patch
+---
+
+Deprecated the `ExtensionFactoryMiddleware` type, which has been moved to `@backstage/frontend-app-api`.
diff --git a/packages/frontend-app-api/report.api.md b/packages/frontend-app-api/report.api.md
index 47677b8916..bf69cc83e6 100644
--- a/packages/frontend-app-api/report.api.md
+++ b/packages/frontend-app-api/report.api.md
@@ -4,10 +4,13 @@
 
 ```ts
 import { ApiHolder } from '@backstage/core-plugin-api';
+import { ApiHolder as ApiHolder_2 } from '@backstage/frontend-plugin-api';
 import { AppNode } from '@backstage/frontend-plugin-api';
 import { AppTree } from '@backstage/frontend-plugin-api';
 import { ConfigApi } from '@backstage/core-plugin-api';
-import { ExtensionFactoryMiddleware } from '@backstage/frontend-plugin-api';
+import { ExtensionDataContainer } from '@backstage/frontend-plugin-api';
+import { ExtensionDataRef } from '@backstage/frontend-plugin-api';
+import { ExtensionDataValue } from '@backstage/frontend-plugin-api';
 import { ExternalRouteRef } from '@backstage/frontend-plugin-api';
 import { FrontendFeature } from '@backstage/frontend-plugin-api';
 import { FrontendPlugin } from '@backstage/frontend-plugin-api';
@@ -176,6 +179,18 @@ export type CreateSpecializedAppOptions = {
   };
 };
 
+// @public (undocumented)
+export type ExtensionFactoryMiddleware = (
+  originalFactory: (contextOverrides?: {
+    config?: JsonObject;
+  }) => ExtensionDataContainer<ExtensionDataRef>,
+  context: {
+    node: AppNode;
+    apis: ApiHolder_2;
+    config?: JsonObject;
+  },
+) => Iterable<ExtensionDataValue<any, any>>;
+
 // @public
 export type FrontendPluginInfoResolver = (ctx: {
   packageJson(): Promise<JsonObject | undefined>;
diff --git a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
index b1da35313e..fcef41daec 100644
--- a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
+++ b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
@@ -19,7 +19,6 @@ import {
   Extension,
   ExtensionDataRef,
   ExtensionDefinition,
-  ExtensionFactoryMiddleware,
   ExtensionInput,
   PortableSchema,
   ResolvedExtensionInput,
@@ -29,6 +28,7 @@ import {
   createExtensionInput,
   createFrontendPlugin,
 } from '@backstage/frontend-plugin-api';
+import { ExtensionFactoryMiddleware } from '../wiring/types';
 import {
   createAppNodeInstance,
   instantiateAppNodeTree,
diff --git a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.ts b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.ts
index 070cf1d687..9e8e3cc2eb 100644
--- a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.ts
+++ b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.ts
@@ -18,10 +18,10 @@ import {
   ApiHolder,
   ExtensionDataContainer,
   ExtensionDataRef,
-  ExtensionFactoryMiddleware,
   ExtensionInput,
   ResolvedExtensionInputs,
 } from '@backstage/frontend-plugin-api';
+import { ExtensionFactoryMiddleware } from '../wiring/types';
 import mapValues from 'lodash/mapValues';
 import { AppNode, AppNodeInstance } from '@backstage/frontend-plugin-api';
 // eslint-disable-next-line @backstage/no-relative-monorepo-imports
diff --git a/packages/frontend-app-api/src/wiring/createSpecializedApp.tsx b/packages/frontend-app-api/src/wiring/createSpecializedApp.tsx
index a5195d853c..680ba6dce5 100644
--- a/packages/frontend-app-api/src/wiring/createSpecializedApp.tsx
+++ b/packages/frontend-app-api/src/wiring/createSpecializedApp.tsx
@@ -29,9 +29,9 @@ import {
   createApiFactory,
   routeResolutionApiRef,
   AppNode,
-  ExtensionFactoryMiddleware,
   FrontendFeature,
 } from '@backstage/frontend-plugin-api';
+import { ExtensionFactoryMiddleware } from './types';
 import {
   AnyApiFactory,
   ApiHolder,
diff --git a/packages/frontend-app-api/src/wiring/index.ts b/packages/frontend-app-api/src/wiring/index.ts
index 1e18859ddd..cae2117df5 100644
--- a/packages/frontend-app-api/src/wiring/index.ts
+++ b/packages/frontend-app-api/src/wiring/index.ts
@@ -20,3 +20,4 @@ export {
 } from './createSpecializedApp';
 export { type FrontendPluginInfoResolver } from './createPluginInfoAttacher';
 export { type AppError, type AppErrorTypes } from './createErrorCollector';
+export { type ExtensionFactoryMiddleware } from './types';
diff --git a/packages/frontend-app-api/src/wiring/types.ts b/packages/frontend-app-api/src/wiring/types.ts
new file mode 100644
index 0000000000..0bb7497179
--- /dev/null
+++ b/packages/frontend-app-api/src/wiring/types.ts
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { JsonObject } from '@backstage/types';
+import {
+  ApiHolder,
+  AppNode,
+  ExtensionDataContainer,
+  ExtensionDataRef,
+  ExtensionDataValue,
+} from '@backstage/frontend-plugin-api';
+
+/** @public */
+export type ExtensionFactoryMiddleware = (
+  originalFactory: (contextOverrides?: {
+    config?: JsonObject;
+  }) => ExtensionDataContainer<ExtensionDataRef>,
+  context: {
+    node: AppNode;
+    apis: ApiHolder;
+    config?: JsonObject;
+  },
+) => Iterable<ExtensionDataValue<any, any>>;
diff --git a/packages/frontend-defaults/report.api.md b/packages/frontend-defaults/report.api.md
index cfe4f55b2d..72bd0d785e 100644
--- a/packages/frontend-defaults/report.api.md
+++ b/packages/frontend-defaults/report.api.md
@@ -8,7 +8,7 @@ import { AppErrorTypes } from '@backstage/frontend-app-api';
 import { Config } from '@backstage/config';
 import { ConfigApi } from '@backstage/frontend-plugin-api';
 import { CreateAppRouteBinder } from '@backstage/frontend-app-api';
-import { ExtensionFactoryMiddleware } from '@backstage/frontend-plugin-api';
+import { ExtensionFactoryMiddleware } from '@backstage/frontend-app-api';
 import { FrontendFeature } from '@backstage/frontend-plugin-api';
 import { FrontendFeatureLoader } from '@backstage/frontend-plugin-api';
 import { FrontendPluginInfoResolver } from '@backstage/frontend-app-api';
diff --git a/packages/frontend-defaults/src/createApp.tsx b/packages/frontend-defaults/src/createApp.tsx
index fe96b50e31..220a7b743f 100644
--- a/packages/frontend-defaults/src/createApp.tsx
+++ b/packages/frontend-defaults/src/createApp.tsx
@@ -18,7 +18,6 @@ import { JSX, lazy, ReactNode, Suspense } from 'react';
 import {
   ConfigApi,
   coreExtensionData,
-  ExtensionFactoryMiddleware,
   FrontendFeature,
   FrontendFeatureLoader,
 } from '@backstage/frontend-plugin-api';
@@ -31,6 +30,7 @@ import { ConfigReader } from '@backstage/config';
 import {
   CreateAppRouteBinder,
   createSpecializedApp,
+  ExtensionFactoryMiddleware,
   FrontendPluginInfoResolver,
 } from '@backstage/frontend-app-api';
 import appPlugin from '@backstage/plugin-app';
diff --git a/packages/frontend-plugin-api/report.api.md b/packages/frontend-plugin-api/report.api.md
index 15450efbdd..0ce1c78757 100644
--- a/packages/frontend-plugin-api/report.api.md
+++ b/packages/frontend-plugin-api/report.api.md
@@ -1215,7 +1215,7 @@ export type ExtensionDefinitionParameters = {
   params?: object | ExtensionBlueprintDefineParams;
 };
 
-// @public (undocumented)
+// @public @deprecated (undocumented)
 export type ExtensionFactoryMiddleware = (
   originalFactory: (contextOverrides?: {
     config?: JsonObject;
diff --git a/packages/frontend-plugin-api/src/wiring/types.ts b/packages/frontend-plugin-api/src/wiring/types.ts
index 0b59e7a7fb..d462803820 100644
--- a/packages/frontend-plugin-api/src/wiring/types.ts
+++ b/packages/frontend-plugin-api/src/wiring/types.ts
@@ -60,7 +60,10 @@ export type ExtensionDataContainer<UExtensionData extends ExtensionDataRef> =
       : never;
   };
 
-/** @public */
+/**
+ * @public
+ * @deprecated Moved to {@link @backstage/frontend-app-api#ExtensionFactoryMiddleware}
+ */
 export type ExtensionFactoryMiddleware = (
   originalFactory: (contextOverrides?: {
     config?: JsonObject;