diff --git a/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/extension-api.interface.ts b/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/extension-api.interface.ts
new file mode 100644
index 0000000000..0183b99fe1
--- /dev/null
+++ b/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/extension-api.interface.ts
@@ -0,0 +1,9 @@
+import type { ManifestBase } from '../types/index.js';
+import type { UmbApi } from './api.interface.js';
+
+/**
+ * Interface for APIs of a Extension.
+ */
+export interface UmbExtensionApi<ManifestType extends ManifestBase = ManifestBase> extends UmbApi {
+	manifest?: ManifestType;
+}
diff --git a/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/index.ts b/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/index.ts
index bb52c4681d..45548d385c 100644
--- a/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/index.ts
+++ b/src/Umbraco.Web.UI.Client/src/libs/extension-api/models/index.ts
@@ -1,2 +1,3 @@
 export * from './entry-point.interface.js';
 export * from './api.interface.js';
+export * from './extension-api.interface.js';