diff --git a/.changeset/mean-pumas-search.md b/.changeset/mean-pumas-search.md
new file mode 100644
index 0000000000..68a3aebc85
--- /dev/null
+++ b/.changeset/mean-pumas-search.md
@@ -0,0 +1,5 @@
+---
+'@backstage/core-app-api': patch
+---
+
+fixed empty body issue for POST requests using FetchAPI with 'plugin://' prefix
diff --git a/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.test.ts b/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.test.ts
index 2f4ec6b536..157abf9d7c 100644
--- a/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.test.ts
+++ b/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.test.ts
@@ -90,4 +90,32 @@ describe('PluginProtocolResolverFetchMiddleware', () => {
       expect(resolve).toHaveBeenLastCalledWith(host);
     },
   );
+
+  it('properly supports transferring request bodies too', async () => {
+    const resolve = jest.fn();
+    const discoveryApi = { getBaseUrl: resolve } as unknown as DiscoveryApi;
+    const middleware = new PluginProtocolResolverFetchMiddleware(discoveryApi);
+    const inner = jest.fn();
+    const outer = middleware.apply(inner);
+
+    resolve.mockResolvedValue('https://elsewhere.com');
+
+    await outer('plugin://a', {
+      method: 'POST',
+      body: '123',
+    });
+
+    expect(inner.mock.calls[0][0]).toBe('https://elsewhere.com');
+    expect(inner.mock.calls[0][1].body).toBe('123');
+
+    await outer(
+      new Request('plugin://a', {
+        method: 'POST',
+        body: '123',
+      }),
+    );
+
+    expect(inner.mock.calls[1][0]).toBe('https://elsewhere.com');
+    expect(inner.mock.calls[1][1].body).toEqual(Buffer.from('123', 'utf8'));
+  });
 });
diff --git a/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.ts b/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.ts
index 72834731fe..6265e8d3d2 100644
--- a/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.ts
+++ b/packages/core-app-api/src/apis/implementations/FetchApi/PluginProtocolResolverFetchMiddleware.ts
@@ -55,7 +55,7 @@ export class PluginProtocolResolverFetchMiddleware implements FetchMiddleware {
       }
 
       const target = `${join(base, pathname)}${search}${hash}`;
-      return next(target, request);
+      return next(target, typeof input === 'string' ? init : input);
     };
   }
 }