diff --git a/app/Api/V1/Controllers/Summary/BasicController.php b/app/Api/V1/Controllers/Summary/BasicController.php
index 6822674139..9c44083daa 100644
--- a/app/Api/V1/Controllers/Summary/BasicController.php
+++ b/app/Api/V1/Controllers/Summary/BasicController.php
@@ -28,6 +28,7 @@ use Carbon\Carbon;
 use Exception;
 use FireflyIII\Api\V1\Controllers\Controller;
 use FireflyIII\Api\V1\Requests\DateRangeRequest;
+use FireflyIII\Api\V1\Requests\Summary\BasicRequest;
 use FireflyIII\Enums\AccountTypeEnum;
 use FireflyIII\Enums\TransactionTypeEnum;
 use FireflyIII\Helpers\Collector\GroupCollectorInterface;
@@ -88,19 +89,10 @@ class BasicController extends Controller
         );
     }
 
-    /**
-     * This endpoint is documented at:
-     * https://api-docs.firefly-iii.org/?urls.primaryName=2.0.0%20(v1)#/summary/getBasicSummary
-     *
-     * @throws Exception
-     */
-    public function basic(DateRangeRequest $request): JsonResponse
+    public function basic(BasicRequest $request): JsonResponse
     {
         // parameters for boxes:
-        $dates        = $request->attributes->all();
-        $start        = $dates['start'];
-        $end          = $dates['end'];
-        $code         = $request->get('currency_code');
+        ['start' => $start, 'end' => $end, 'code' => $code] = $request->attributes->all();
         // balance information:
         $balanceData  = $this->getBalanceInformation($start, $end);
         $billData     = $this->getSubscriptionInformation($start, $end);
@@ -115,7 +107,7 @@ class BasicController extends Controller
         // give new keys
         $return       = [];
         foreach ($total as $entry) {
-            if (null === $code || ($code === $entry['currency_code'])) {
+            if ('' === $code || ($code === $entry['currency_code'])) {
                 $return[$entry['key']] = $entry;
             }
         }
diff --git a/app/Api/V1/Requests/AggregateFormRequest.php b/app/Api/V1/Requests/AggregateFormRequest.php
index 85579fffc3..001c902fda 100644
--- a/app/Api/V1/Requests/AggregateFormRequest.php
+++ b/app/Api/V1/Requests/AggregateFormRequest.php
@@ -25,6 +25,7 @@ namespace FireflyIII\Api\V1\Requests;
 
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Log;
 use Illuminate\Validation\Validator;
 use RuntimeException;
 
@@ -43,12 +44,14 @@ abstract class AggregateFormRequest extends ApiRequest
         parent::initialize($query, $request, $attributes, $cookies, $files, $server, $content);
 
         // instantiate all subrequests and share current requests' bags with them
+        Log::debug('Initializing AggregateFormRequest.');
         foreach ($this->getRequests() as $config) {
             $requestClass         = is_array($config) ? array_shift($config) : $config;
 
             if (!is_a($requestClass, Request::class, true)) {
                 throw new RuntimeException('getRequests() must return class-strings of subclasses of Request');
             }
+            Log::debug(sprintf('Initializing subrequest %s', $requestClass));
 
             $instance             = $this->requests[] = new $requestClass();
             $instance->request    = $this->request;
@@ -63,6 +66,7 @@ abstract class AggregateFormRequest extends ApiRequest
                 $instance->handleConfig(is_array($config) ? $config : []);
             }
         }
+        Log::debug('Done initializing AggregateFormRequest.');
     }
 
     public function rules(): array
@@ -85,6 +89,7 @@ abstract class AggregateFormRequest extends ApiRequest
         // register all subrequests' validators
         foreach ($this->requests as $request) {
             if (method_exists($request, 'withValidator')) {
+                Log::debug(sprintf('Process withValidator from class %s', get_class($request)));
                 $request->withValidator($validator);
             }
         }
diff --git a/app/Api/V1/Requests/DateRangeRequest.php b/app/Api/V1/Requests/DateRangeRequest.php
index a2e3738489..831e7b625c 100644
--- a/app/Api/V1/Requests/DateRangeRequest.php
+++ b/app/Api/V1/Requests/DateRangeRequest.php
@@ -39,8 +39,6 @@ class DateRangeRequest extends ApiRequest
     {
         $validator->after(
             function (Validator $validator): void {
-                $this->attributes->set('start', null);
-                $this->attributes->set('end', null);
                 if (!$validator->valid()) {
                     return;
                 }
diff --git a/app/Api/V1/Requests/Models/TransactionCurrency/CurrencyCodeRequest.php b/app/Api/V1/Requests/Models/TransactionCurrency/CurrencyCodeRequest.php
new file mode 100644
index 0000000000..56d434b57a
--- /dev/null
+++ b/app/Api/V1/Requests/Models/TransactionCurrency/CurrencyCodeRequest.php
@@ -0,0 +1,49 @@
+<?php
+/*
+ * CurrencyCodeRequest.php
+ * Copyright (c) 2025 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace FireflyIII\Api\V1\Requests\Models\TransactionCurrency;
+
+use FireflyIII\Api\V1\Requests\ApiRequest;
+use Illuminate\Validation\Validator;
+
+class CurrencyCodeRequest extends ApiRequest
+{
+
+    public function rules(): array
+    {
+        return [
+            'code' => sprintf('exists:transaction_currencies,code|%s', $this->required),
+        ];
+    }
+
+    public function withValidator(Validator $validator): void
+    {
+        $validator->after(
+            function (Validator $validator): void {
+                if (!$validator->valid()) {
+                    return;
+                }
+                $code = $this->convertString('code', '');
+                $this->attributes->set('code', $code);
+            }
+        );
+    }
+}
diff --git a/app/Api/V1/Requests/Summary/BasicRequest.php b/app/Api/V1/Requests/Summary/BasicRequest.php
new file mode 100644
index 0000000000..0725b129c9
--- /dev/null
+++ b/app/Api/V1/Requests/Summary/BasicRequest.php
@@ -0,0 +1,37 @@
+<?php
+/*
+ * BasicRequest.php
+ * Copyright (c) 2025 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace FireflyIII\Api\V1\Requests\Summary;
+
+use FireflyIII\Api\V1\Requests\AggregateFormRequest;
+use FireflyIII\Api\V1\Requests\DateRangeRequest;
+use FireflyIII\Api\V1\Requests\Models\TransactionCurrency\CurrencyCodeRequest;
+
+class BasicRequest extends AggregateFormRequest
+{
+    protected function getRequests(): array
+    {
+        return [
+            [DateRangeRequest::class, 'required'],
+            CurrencyCodeRequest::class,
+        ];
+    }
+}