first upload all files

Modules/Newsletter/Http/Controllers/SubscriberController.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Modules\Newsletter\Http\Controllers;
+
+use Newsletter;
+use Modules\Newsletter\Http\Requests\StoreSubscriberRequest;
+
+class SubscriberController
+{
+    /**
+     * Store a newly created resource in storage.
+     *
+     * @return \Illuminate\Http\Response
+     */
+    public function store(StoreSubscriberRequest $request)
+    {
+        Newsletter::subscribeOrUpdate($request->email);
+
+        if (! Newsletter::lastActionSucceeded()) {
+            return response()->json([
+                'message' => str_after(Newsletter::getLastError(), '400: '),
+            ], 403);
+        }
+    }
+}

Modules/Newsletter/Http/Requests/StoreSubscriberRequest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Modules\Newsletter\Http\Requests;
+
+use Modules\Core\Http\Requests\Request;
+
+class StoreSubscriberRequest extends Request
+{
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array
+     */
+    public function rules()
+    {
+        return [
+            'email' => ['required', 'email'],
+        ];
+    }
+}