diff --git a/.changeset/long-wolves-return.md b/.changeset/long-wolves-return.md
new file mode 100644
index 0000000000..8d4d78792f
--- /dev/null
+++ b/.changeset/long-wolves-return.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-app-api': patch
+---
+
+Bringing over apis from core-plugin-api
diff --git a/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts b/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
index 43955328a8..2bfd09a3e8 100644
--- a/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
+++ b/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
@@ -15,10 +15,9 @@
  */
 
 import { RouteRef, coreExtensionData } from '@backstage/frontend-plugin-api';
-// eslint-disable-next-line @backstage/no-relative-monorepo-imports
-import { toLegacyPlugin } from '../wiring/createApp';
 import { BackstageRouteObject } from './types';
 import { AppNode } from '@backstage/frontend-plugin-api';
+import { toLegacyPlugin } from './toLegacyPlugin';
 
 // We always add a child that matches all subroutes but without any route refs. This makes
 // sure that we're always able to match each route no matter how deep the navigation goes.
diff --git a/packages/frontend-app-api/src/routing/toLegacyPlugin.ts b/packages/frontend-app-api/src/routing/toLegacyPlugin.ts
new file mode 100644
index 0000000000..2d04d04dda
--- /dev/null
+++ b/packages/frontend-app-api/src/routing/toLegacyPlugin.ts
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2023 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 { BackstagePlugin } from '@backstage/frontend-plugin-api';
+import { BackstagePlugin as LegacyBackstagePlugin } from '@backstage/core-plugin-api';
+import { getOrCreateGlobalSingleton } from '@backstage/version-bridge';
+
+// Make sure that we only convert each new plugin instance to its legacy equivalent once
+const legacyPluginStore = getOrCreateGlobalSingleton(
+  'legacy-plugin-compatibility-store',
+  () => new WeakMap<BackstagePlugin, LegacyBackstagePlugin>(),
+);
+
+export function toLegacyPlugin(plugin: BackstagePlugin): LegacyBackstagePlugin {
+  let legacy = legacyPluginStore.get(plugin);
+  if (legacy) {
+    return legacy;
+  }
+
+  const errorMsg = 'Not implemented in legacy plugin compatibility layer';
+  const notImplemented = () => {
+    throw new Error(errorMsg);
+  };
+
+  legacy = {
+    getId(): string {
+      return plugin.id;
+    },
+    get routes() {
+      return {};
+    },
+    get externalRoutes() {
+      return {};
+    },
+    getApis: notImplemented,
+    getFeatureFlags: notImplemented,
+    provide: notImplemented,
+  };
+
+  legacyPluginStore.set(plugin, legacy);
+  return legacy;
+}
diff --git a/packages/frontend-app-api/src/wiring/createApp.tsx b/packages/frontend-app-api/src/wiring/createApp.tsx
index 8495f961db..d39111eb99 100644
--- a/packages/frontend-app-api/src/wiring/createApp.tsx
+++ b/packages/frontend-app-api/src/wiring/createApp.tsx
@@ -80,7 +80,6 @@ import { BrowserRouter, Route } from 'react-router-dom';
 import { SidebarItem } from '@backstage/core-components';
 import { DarkTheme, LightTheme } from '../extensions/themes';
 import { extractRouteInfoFromAppNode } from '../routing/extractRouteInfoFromAppNode';
-import { getOrCreateGlobalSingleton } from '@backstage/version-bridge';
 import {
   appLanguageApiRef,
   translationApiRef,
@@ -91,6 +90,7 @@ import { resolveRouteBindings } from '../routing/resolveRouteBindings';
 import { collectRouteIds } from '../routing/collectRouteIds';
 import { createAppTree } from '../tree';
 import { AppNode } from '@backstage/frontend-plugin-api';
+import { toLegacyPlugin } from '../routing/toLegacyPlugin';
 
 const builtinExtensions = [
   Core,
@@ -328,42 +328,6 @@ export function createSpecializedApp(options?: {
   };
 }
 
-// Make sure that we only convert each new plugin instance to its legacy equivalent once
-const legacyPluginStore = getOrCreateGlobalSingleton(
-  'legacy-plugin-compatibility-store',
-  () => new WeakMap<BackstagePlugin, LegacyBackstagePlugin>(),
-);
-
-export function toLegacyPlugin(plugin: BackstagePlugin): LegacyBackstagePlugin {
-  let legacy = legacyPluginStore.get(plugin);
-  if (legacy) {
-    return legacy;
-  }
-
-  const errorMsg = 'Not implemented in legacy plugin compatibility layer';
-  const notImplemented = () => {
-    throw new Error(errorMsg);
-  };
-
-  legacy = {
-    getId(): string {
-      return plugin.id;
-    },
-    get routes() {
-      return {};
-    },
-    get externalRoutes() {
-      return {};
-    },
-    getApis: notImplemented,
-    getFeatureFlags: notImplemented,
-    provide: notImplemented,
-  };
-
-  legacyPluginStore.set(plugin, legacy);
-  return legacy;
-}
-
 function createLegacyAppContext(plugins: BackstagePlugin[]): AppContext {
   return {
     getPlugins(): LegacyBackstagePlugin[] {
diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index 794da9617b..f1537fd5b7 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -5,19 +5,90 @@
 ```ts
 /// <reference types="react" />
 
+import { AlertApi } from '@backstage/core-plugin-api';
+import { alertApiRef } from '@backstage/core-plugin-api';
+import { AlertMessage } from '@backstage/core-plugin-api';
 import { AnyApiFactory } from '@backstage/core-plugin-api';
 import { AnyApiRef } from '@backstage/core-plugin-api';
+import { ApiFactory } from '@backstage/core-plugin-api';
+import { ApiHolder } from '@backstage/core-plugin-api';
 import { ApiRef } from '@backstage/core-plugin-api';
+import { ApiRefConfig } from '@backstage/core-plugin-api';
 import { AppTheme } from '@backstage/core-plugin-api';
-import { IconComponent } from '@backstage/core-plugin-api';
+import { AppThemeApi } from '@backstage/core-plugin-api';
+import { appThemeApiRef } from '@backstage/core-plugin-api';
+import { atlassianAuthApiRef } from '@backstage/core-plugin-api';
+import { AuthProviderInfo } from '@backstage/core-plugin-api';
+import { AuthRequestOptions } from '@backstage/core-plugin-api';
+import { BackstageIdentityApi } from '@backstage/core-plugin-api';
+import { BackstageIdentityResponse } from '@backstage/core-plugin-api';
+import { BackstageUserIdentity } from '@backstage/core-plugin-api';
+import { bitbucketAuthApiRef } from '@backstage/core-plugin-api';
+import { bitbucketServerAuthApiRef } from '@backstage/core-plugin-api';
+import { ComponentType } from 'react';
+import { ConfigApi } from '@backstage/core-plugin-api';
+import { configApiRef } from '@backstage/core-plugin-api';
+import { createApiFactory } from '@backstage/core-plugin-api';
+import { createApiRef } from '@backstage/core-plugin-api';
+import { DiscoveryApi } from '@backstage/core-plugin-api';
+import { discoveryApiRef } from '@backstage/core-plugin-api';
+import { ErrorApi } from '@backstage/core-plugin-api';
+import { ErrorApiError } from '@backstage/core-plugin-api';
+import { ErrorApiErrorContext } from '@backstage/core-plugin-api';
+import { errorApiRef } from '@backstage/core-plugin-api';
+import { FeatureFlag } from '@backstage/core-plugin-api';
+import { FeatureFlagsApi } from '@backstage/core-plugin-api';
+import { featureFlagsApiRef } from '@backstage/core-plugin-api';
+import { FeatureFlagsSaveOptions } from '@backstage/core-plugin-api';
+import { FeatureFlagState } from '@backstage/core-plugin-api';
+import { FetchApi } from '@backstage/core-plugin-api';
+import { fetchApiRef } from '@backstage/core-plugin-api';
+import { githubAuthApiRef } from '@backstage/core-plugin-api';
+import { gitlabAuthApiRef } from '@backstage/core-plugin-api';
+import { googleAuthApiRef } from '@backstage/core-plugin-api';
+import { IconComponent as IconComponent_2 } from '@backstage/core-plugin-api';
+import { IdentityApi } from '@backstage/core-plugin-api';
+import { identityApiRef } from '@backstage/core-plugin-api';
 import { JsonObject } from '@backstage/types';
 import { JSX as JSX_2 } from 'react';
+import { microsoftAuthApiRef } from '@backstage/core-plugin-api';
+import { OAuthApi } from '@backstage/core-plugin-api';
+import { OAuthRequestApi } from '@backstage/core-plugin-api';
+import { oauthRequestApiRef } from '@backstage/core-plugin-api';
+import { OAuthRequester } from '@backstage/core-plugin-api';
+import { OAuthRequesterOptions } from '@backstage/core-plugin-api';
+import { OAuthScope } from '@backstage/core-plugin-api';
+import { oktaAuthApiRef } from '@backstage/core-plugin-api';
+import { oneloginAuthApiRef } from '@backstage/core-plugin-api';
+import { OpenIdConnectApi } from '@backstage/core-plugin-api';
+import { PendingOAuthRequest } from '@backstage/core-plugin-api';
+import { ProfileInfo } from '@backstage/core-plugin-api';
+import { ProfileInfoApi } from '@backstage/core-plugin-api';
 import { default as React_2 } from 'react';
 import { ReactNode } from 'react';
+import { SessionApi } from '@backstage/core-plugin-api';
+import { SessionState } from '@backstage/core-plugin-api';
+import { StorageApi } from '@backstage/core-plugin-api';
+import { storageApiRef } from '@backstage/core-plugin-api';
+import { StorageValueSnapshot } from '@backstage/core-plugin-api';
+import { TypesToApiRefs } from '@backstage/core-plugin-api';
+import { useApi } from '@backstage/core-plugin-api';
+import { useApiHolder } from '@backstage/core-plugin-api';
+import { withApis } from '@backstage/core-plugin-api';
 import { z } from 'zod';
 import { ZodSchema } from 'zod';
 import { ZodTypeDef } from 'zod';
 
+export { AlertApi };
+
+export { alertApiRef };
+
+export { AlertMessage };
+
+export { AnyApiFactory };
+
+export { AnyApiRef };
+
 // @public (undocumented)
 export type AnyExtensionDataMap = {
   [name in string]: ExtensionDataRef<
@@ -56,6 +127,14 @@ export type AnyRoutes = {
   [name in string]: RouteRef;
 };
 
+export { ApiFactory };
+
+export { ApiHolder };
+
+export { ApiRef };
+
+export { ApiRefConfig };
+
 // @public
 export interface AppNode {
   readonly edges: AppNodeEdges;
@@ -99,6 +178,12 @@ export interface AppNodeSpec {
   readonly source?: BackstagePlugin;
 }
 
+export { AppTheme };
+
+export { AppThemeApi };
+
+export { appThemeApiRef };
+
 // @public
 export interface AppTree {
   readonly nodes: ReadonlyMap<string, AppNode>;
@@ -116,6 +201,16 @@ export interface AppTreeApi {
 // @public
 export const appTreeApiRef: ApiRef<AppTreeApi>;
 
+export { atlassianAuthApiRef };
+
+export { AuthProviderInfo };
+
+export { AuthRequestOptions };
+
+export { BackstageIdentityApi };
+
+export { BackstageIdentityResponse };
+
 // @public (undocumented)
 export interface BackstagePlugin<
   Routes extends AnyRoutes = AnyRoutes,
@@ -133,6 +228,16 @@ export interface BackstagePlugin<
   routes: Routes;
 }
 
+export { BackstageUserIdentity };
+
+export { bitbucketAuthApiRef };
+
+export { bitbucketServerAuthApiRef };
+
+export { ConfigApi };
+
+export { configApiRef };
+
 // @public (undocumented)
 export interface ConfigurableExtensionDataRef<
   TData,
@@ -181,6 +286,10 @@ export function createApiExtension<
   },
 ): Extension<TConfig>;
 
+export { createApiFactory };
+
+export { createApiRef };
+
 // @public (undocumented)
 export function createExtension<
   TOutput extends AnyExtensionDataMap,
@@ -277,7 +386,7 @@ export function createNavItemExtension(options: {
   id: string;
   routeRef: RouteRef<undefined>;
   title: string;
-  icon: IconComponent;
+  icon: IconComponent_2;
 }): Extension<{
   title: string;
 }>;
@@ -357,6 +466,18 @@ export function createSubRouteRef<
 // @public (undocumented)
 export function createThemeExtension(theme: AppTheme): Extension<never>;
 
+export { DiscoveryApi };
+
+export { discoveryApiRef };
+
+export { ErrorApi };
+
+export { ErrorApiError };
+
+export { ErrorApiErrorContext };
+
+export { errorApiRef };
+
 // @public (undocumented)
 export interface Extension<TConfig> {
   // (undocumented)
@@ -488,13 +609,69 @@ export interface ExternalRouteRef<
   readonly T: TParams;
 }
 
+export { FeatureFlag };
+
+export { FeatureFlagsApi };
+
+export { featureFlagsApiRef };
+
+export { FeatureFlagsSaveOptions };
+
+export { FeatureFlagState };
+
+export { FetchApi };
+
+export { fetchApiRef };
+
+export { githubAuthApiRef };
+
+export { gitlabAuthApiRef };
+
+export { googleAuthApiRef };
+
+// @public
+export type IconComponent = ComponentType<
+  | {
+      fontSize?: 'large' | 'small' | 'default' | 'inherit';
+    }
+  | {
+      fontSize?: 'medium' | 'large' | 'small' | 'inherit';
+    }
+>;
+
+export { IdentityApi };
+
+export { identityApiRef };
+
+export { microsoftAuthApiRef };
+
 // @public (undocumented)
 export type NavTarget = {
   title: string;
-  icon: IconComponent;
+  icon: IconComponent_2;
   routeRef: RouteRef<undefined>;
 };
 
+export { OAuthApi };
+
+export { OAuthRequestApi };
+
+export { oauthRequestApiRef };
+
+export { OAuthRequester };
+
+export { OAuthRequesterOptions };
+
+export { OAuthScope };
+
+export { oktaAuthApiRef };
+
+export { oneloginAuthApiRef };
+
+export { OpenIdConnectApi };
+
+export { PendingOAuthRequest };
+
 // @public (undocumented)
 export interface PluginOptions<
   Routes extends AnyRoutes,
@@ -516,6 +693,10 @@ export type PortableSchema<TOutput> = {
   schema: JsonObject;
 };
 
+export { ProfileInfo };
+
+export { ProfileInfoApi };
+
 // @public
 export type RouteFunc<TParams extends AnyRouteRefParams> = (
   ...[params]: TParams extends undefined
@@ -533,6 +714,16 @@ export interface RouteRef<
   readonly T: TParams;
 }
 
+export { SessionApi };
+
+export { SessionState };
+
+export { StorageApi };
+
+export { storageApiRef };
+
+export { StorageValueSnapshot };
+
 // @public
 export interface SubRouteRef<
   TParams extends AnyRouteRefParams = AnyRouteRefParams,
@@ -545,6 +736,12 @@ export interface SubRouteRef<
   readonly T: TParams;
 }
 
+export { TypesToApiRefs };
+
+export { useApi };
+
+export { useApiHolder };
+
 // @public
 export function useRouteRef<
   TOptional extends boolean,
@@ -562,4 +759,6 @@ export function useRouteRef<TParams extends AnyRouteRefParams>(
 export function useRouteRefParams<Params extends AnyRouteRefParams>(
   _routeRef: RouteRef<Params> | SubRouteRef<Params>,
 ): Params;
+
+export { withApis };
 ```
diff --git a/packages/frontend-plugin-api/package.json b/packages/frontend-plugin-api/package.json
index 2a1d741d3d..d7d19e3d74 100644
--- a/packages/frontend-plugin-api/package.json
+++ b/packages/frontend-plugin-api/package.json
@@ -39,6 +39,7 @@
     "react-router-dom": "6.0.0-beta.0 || ^6.3.0"
   },
   "dependencies": {
+    "@backstage/config": "workspace:^",
     "@backstage/core-components": "workspace:^",
     "@backstage/core-plugin-api": "workspace:^",
     "@backstage/types": "workspace:^",
diff --git a/packages/frontend-plugin-api/src/apis/definitions/AlertApi.ts b/packages/frontend-plugin-api/src/apis/definitions/AlertApi.ts
new file mode 100644
index 0000000000..649a930b50
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/AlertApi.ts
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type AlertApi,
+  type AlertMessage,
+  alertApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/AppLanguageApi.ts b/packages/frontend-plugin-api/src/apis/definitions/AppLanguageApi.ts
new file mode 100644
index 0000000000..37ffcfa820
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/AppLanguageApi.ts
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export {
+  type AppLanguageApi,
+  appLanguageApiRef,
+} from '@backstage/core-plugin-api/alpha';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/AppThemeApi.ts b/packages/frontend-plugin-api/src/apis/definitions/AppThemeApi.ts
new file mode 100644
index 0000000000..ce62cd72c3
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/AppThemeApi.ts
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type AppTheme,
+  type AppThemeApi,
+  appThemeApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/ConfigApi.ts b/packages/frontend-plugin-api/src/apis/definitions/ConfigApi.ts
new file mode 100644
index 0000000000..968a2843ba
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/ConfigApi.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export { type ConfigApi, configApiRef } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/DiscoveryApi.ts b/packages/frontend-plugin-api/src/apis/definitions/DiscoveryApi.ts
new file mode 100644
index 0000000000..98b3f0bbf0
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/DiscoveryApi.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export { type DiscoveryApi, discoveryApiRef } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/ErrorApi.ts b/packages/frontend-plugin-api/src/apis/definitions/ErrorApi.ts
new file mode 100644
index 0000000000..57782a05dc
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/ErrorApi.ts
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type ErrorApiError,
+  type ErrorApiErrorContext,
+  type ErrorApi,
+  errorApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/FeatureFlagsApi.ts b/packages/frontend-plugin-api/src/apis/definitions/FeatureFlagsApi.ts
new file mode 100644
index 0000000000..820efc0a25
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/FeatureFlagsApi.ts
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type FeatureFlag,
+  type FeatureFlagState,
+  type FeatureFlagsSaveOptions,
+  type FeatureFlagsApi,
+  featureFlagsApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/FetchApi.ts b/packages/frontend-plugin-api/src/apis/definitions/FetchApi.ts
new file mode 100644
index 0000000000..bcc9bc6a91
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/FetchApi.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2021 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.
+ */
+
+export { type FetchApi, fetchApiRef } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/IdentityApi.ts b/packages/frontend-plugin-api/src/apis/definitions/IdentityApi.ts
new file mode 100644
index 0000000000..03503a8fba
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/IdentityApi.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export { type IdentityApi, identityApiRef } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/OAuthRequestApi.ts b/packages/frontend-plugin-api/src/apis/definitions/OAuthRequestApi.ts
new file mode 100644
index 0000000000..ff7a0f2852
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/OAuthRequestApi.ts
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type OAuthRequesterOptions,
+  type OAuthRequester,
+  type PendingOAuthRequest,
+  type OAuthRequestApi,
+  oauthRequestApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/StorageApi.ts b/packages/frontend-plugin-api/src/apis/definitions/StorageApi.ts
new file mode 100644
index 0000000000..2309d2414c
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/StorageApi.ts
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type StorageValueSnapshot,
+  type StorageApi,
+  storageApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/alpha.ts b/packages/frontend-plugin-api/src/apis/definitions/alpha.ts
new file mode 100644
index 0000000000..a4ccde1170
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/alpha.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export { appLanguageApiRef, type AppLanguageApi } from './AppLanguageApi';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/auth.ts b/packages/frontend-plugin-api/src/apis/definitions/auth.ts
new file mode 100644
index 0000000000..d27aebbf47
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/definitions/auth.ts
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type BackstageIdentityApi,
+  type BackstageIdentityResponse,
+  type BackstageUserIdentity,
+  type AuthProviderInfo,
+  type AuthRequestOptions,
+  type OAuthScope,
+  type OAuthApi,
+  type OpenIdConnectApi,
+  type ProfileInfoApi,
+  type ProfileInfo,
+  type SessionApi,
+  SessionState,
+  atlassianAuthApiRef,
+  bitbucketAuthApiRef,
+  bitbucketServerAuthApiRef,
+  githubAuthApiRef,
+  gitlabAuthApiRef,
+  googleAuthApiRef,
+  oktaAuthApiRef,
+  microsoftAuthApiRef,
+  oneloginAuthApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/definitions/index.ts b/packages/frontend-plugin-api/src/apis/definitions/index.ts
index 8facdca2ca..420942cb19 100644
--- a/packages/frontend-plugin-api/src/apis/definitions/index.ts
+++ b/packages/frontend-plugin-api/src/apis/definitions/index.ts
@@ -23,3 +23,22 @@ export {
   type AppTree,
   type AppTreeApi,
 } from './AppTreeApi';
+
+// This folder contains definitions for all core APIs.
+//
+// Plugins should rely on these APIs for functionality as much as possible.
+//
+// If you think some API definition is missing, please open an Issue or send a PR!
+
+export * from './auth';
+
+export * from './AlertApi';
+export * from './AppThemeApi';
+export * from './ConfigApi';
+export * from './DiscoveryApi';
+export * from './ErrorApi';
+export * from './FeatureFlagsApi';
+export * from './FetchApi';
+export * from './IdentityApi';
+export * from './OAuthRequestApi';
+export * from './StorageApi';
diff --git a/packages/frontend-plugin-api/src/apis/index.ts b/packages/frontend-plugin-api/src/apis/index.ts
index 5a012c0553..5def6cb0f9 100644
--- a/packages/frontend-plugin-api/src/apis/index.ts
+++ b/packages/frontend-plugin-api/src/apis/index.ts
@@ -15,3 +15,4 @@
  */
 
 export * from './definitions';
+export * from './system';
diff --git a/packages/frontend-plugin-api/src/apis/system/ApiRef.ts b/packages/frontend-plugin-api/src/apis/system/ApiRef.ts
new file mode 100644
index 0000000000..0d1f8312cb
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/system/ApiRef.ts
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export {
+  type ApiRef,
+  type ApiRefConfig,
+  createApiRef,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/system/helpers.ts b/packages/frontend-plugin-api/src/apis/system/helpers.ts
new file mode 100644
index 0000000000..5de265be99
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/system/helpers.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export { createApiFactory } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/system/index.ts b/packages/frontend-plugin-api/src/apis/system/index.ts
new file mode 100644
index 0000000000..b1bd3ac2b3
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/system/index.ts
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export { useApi, useApiHolder, withApis } from './useApi';
+export { createApiRef } from './ApiRef';
+export type { ApiRefConfig } from './ApiRef';
+export * from './types';
+export * from './helpers';
diff --git a/packages/frontend-plugin-api/src/apis/system/types.ts b/packages/frontend-plugin-api/src/apis/system/types.ts
new file mode 100644
index 0000000000..cc44e19e3f
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/system/types.ts
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export type {
+  ApiRef,
+  AnyApiRef,
+  TypesToApiRefs,
+  ApiHolder,
+  ApiFactory,
+  AnyApiFactory,
+} from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/apis/system/useApi.tsx b/packages/frontend-plugin-api/src/apis/system/useApi.tsx
new file mode 100644
index 0000000000..d2efa49fa1
--- /dev/null
+++ b/packages/frontend-plugin-api/src/apis/system/useApi.tsx
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2023 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.
+ */
+
+export { useApiHolder, useApi, withApis } from '@backstage/core-plugin-api';
diff --git a/packages/frontend-plugin-api/src/icons/index.ts b/packages/frontend-plugin-api/src/icons/index.ts
new file mode 100644
index 0000000000..9c9e45e54c
--- /dev/null
+++ b/packages/frontend-plugin-api/src/icons/index.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 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.
+ */
+
+export type { IconComponent } from './types';
diff --git a/packages/frontend-plugin-api/src/icons/types.ts b/packages/frontend-plugin-api/src/icons/types.ts
new file mode 100644
index 0000000000..4d54629de2
--- /dev/null
+++ b/packages/frontend-plugin-api/src/icons/types.ts
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 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 { ComponentType } from 'react';
+
+/**
+ * IconComponent is the common icon type used throughout Backstage when
+ * working with and rendering generic icons, including the app system icons.
+ *
+ * @remarks
+ *
+ * The type is based on SvgIcon from Material UI, but both do not what the plugin-api
+ * package to have a dependency on Material UI, nor do we want the props to be as broad
+ * as the SvgIconProps interface.
+ *
+ * If you have the need to forward additional props from SvgIconProps, you can
+ * open an issue or submit a PR to the main Backstage repo. When doing so please
+ * also describe your use-case and reasoning of the addition.
+ *
+ * @public
+ */
+
+export type IconComponent = ComponentType<
+  /* Material UI v4 */
+  | {
+      fontSize?: 'large' | 'small' | 'default' | 'inherit';
+    }
+  /* Material UI v5: https://mui.com/material-ui/migration/v5-component-changes/#icon */
+  | {
+      fontSize?: 'medium' | 'large' | 'small' | 'inherit';
+    }
+>;
diff --git a/packages/frontend-plugin-api/src/index.ts b/packages/frontend-plugin-api/src/index.ts
index 498bc96a77..3248e79945 100644
--- a/packages/frontend-plugin-api/src/index.ts
+++ b/packages/frontend-plugin-api/src/index.ts
@@ -23,6 +23,8 @@
 export * from './apis';
 export * from './components';
 export * from './extensions';
+export * from './icons';
 export * from './routing';
 export * from './schema';
+export * from './apis/system';
 export * from './wiring';
diff --git a/yarn.lock b/yarn.lock
index 608d608907..44d83b5d4a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4046,6 +4046,7 @@ __metadata:
   resolution: "@backstage/frontend-plugin-api@workspace:packages/frontend-plugin-api"
   dependencies:
     "@backstage/cli": "workspace:^"
+    "@backstage/config": "workspace:^"
     "@backstage/core-components": "workspace:^"
     "@backstage/core-plugin-api": "workspace:^"
     "@backstage/frontend-app-api": "workspace:^"