diff --git a/src/Extend/Settings.php b/src/Extend/Settings.php
new file mode 100644
index 0000000000..a2c66b2191
--- /dev/null
+++ b/src/Extend/Settings.php
@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extend;
+
+use Flarum\Api\Serializer\AbstractSerializer;
+use Flarum\Api\Serializer\ForumSerializer;
+use Flarum\Extension\Extension;
+use Flarum\Foundation\ContainerUtil;
+use Flarum\Settings\SettingsRepositoryInterface;
+use Illuminate\Contracts\Container\Container;
+
+class Settings implements ExtenderInterface
+{
+    private $settings = [];
+
+    /**
+     * Serialize a setting value to the ForumSerializer attributes.
+     *
+     * @param string $attributeName: The attribute name to be used in the ForumSerializer attributes array.
+     * @param string $key: The key of the setting.
+     * @param string|callable|null $callback: Optional callback to modify the value before serialization.
+     * @return $this
+     */
+    public function serializeToForum(string $attributeName, string $key, $callback = null)
+    {
+        $this->settings[$key] = compact('attributeName', 'callback');
+
+        return $this;
+    }
+
+    public function extend(Container $container, Extension $extension = null)
+    {
+        if (! empty($this->settings)) {
+            AbstractSerializer::addMutator(
+                ForumSerializer::class,
+                function () use ($container) {
+                    $settings = $container->make(SettingsRepositoryInterface::class);
+                    $attributes = [];
+
+                    foreach ($this->settings as $key => $setting) {
+                        $value = $settings->get($key, null);
+
+                        if (isset($setting['callback'])) {
+                            $callback = ContainerUtil::wrapCallback($setting['callback'], $container);
+                            $value = $callback($value);
+                        }
+
+                        $attributes[$setting['attributeName']] = $value;
+                    }
+
+                    return $attributes;
+                }
+            );
+        }
+    }
+}
diff --git a/tests/integration/extenders/ApiSerializerTest.php b/tests/integration/extenders/ApiSerializerTest.php
index 6e08ae9eaf..2bee2bafd8 100644
--- a/tests/integration/extenders/ApiSerializerTest.php
+++ b/tests/integration/extenders/ApiSerializerTest.php
@@ -45,15 +45,6 @@ protected function prepDb()
         ]);
     }
 
-    protected function prepSettingsDb()
-    {
-        $this->prepareDatabase([
-            'settings' => [
-                ['key' => 'customPrefix.customSetting', 'value' => 'customValue']
-            ],
-        ]);
-    }
-
     /**
      * @test
      */
diff --git a/tests/integration/extenders/SettingsTest.php b/tests/integration/extenders/SettingsTest.php
new file mode 100644
index 0000000000..854c01465f
--- /dev/null
+++ b/tests/integration/extenders/SettingsTest.php
@@ -0,0 +1,133 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\integration\extenders;
+
+use Flarum\Extend;
+use Flarum\Tests\integration\RetrievesAuthorizedUsers;
+use Flarum\Tests\integration\TestCase;
+
+class SettingsTest extends TestCase
+{
+    use RetrievesAuthorizedUsers;
+
+    protected function prepDb()
+    {
+        $this->prepareDatabase([
+            'users' => [
+                $this->adminUser(),
+                $this->normalUser()
+            ],
+            'settings' => [
+                ['key' => 'custom-prefix.custom_setting', 'value' => 'customValue'],
+                ['key' => 'custom-prefix.custom_setting2', 'value' => 'customValue']
+            ]
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function custom_setting_isnt_serialized_by_default()
+    {
+        $this->prepDb();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody(), true);
+
+        $this->assertArrayNotHasKey('customPrefix.customSetting', $payload['data']['attributes']);
+    }
+
+    /**
+     * @test
+     */
+    public function custom_setting_serialized_if_added()
+    {
+        $this->extend(
+            (new Extend\Settings())
+                ->serializeToForum('customPrefix.customSetting', 'custom-prefix.custom_setting')
+        );
+
+        $this->prepDb();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody(), true);
+
+        $this->assertArrayHasKey('customPrefix.customSetting', $payload['data']['attributes']);
+        $this->assertEquals('customValue', $payload['data']['attributes']['customPrefix.customSetting']);
+    }
+
+    /**
+     * @test
+     */
+    public function custom_setting_callback_works_if_added()
+    {
+        $this->extend(
+            (new Extend\Settings())
+                ->serializeToForum('customPrefix.customSetting', 'custom-prefix.custom_setting', function ($value) {
+                    return $value.'Modified';
+                })
+        );
+
+        $this->prepDb();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody(), true);
+
+        $this->assertArrayHasKey('customPrefix.customSetting', $payload['data']['attributes']);
+        $this->assertEquals('customValueModified', $payload['data']['attributes']['customPrefix.customSetting']);
+    }
+
+    /**
+     * @test
+     */
+    public function custom_setting_callback_works_with_invokable_class()
+    {
+        $this->extend(
+            (new Extend\Settings())
+                ->serializeToForum('customPrefix.customSetting2', 'custom-prefix.custom_setting2', CustomInvokableClass::class)
+        );
+
+        $this->prepDb();
+
+        $response = $this->send(
+            $this->request('GET', '/api', [
+                'authenticatedAs' => 1,
+            ])
+        );
+
+        $payload = json_decode($response->getBody(), true);
+
+        $this->assertArrayHasKey('customPrefix.customSetting2', $payload['data']['attributes']);
+        $this->assertEquals('customValueModifiedByInvokable', $payload['data']['attributes']['customPrefix.customSetting2']);
+    }
+}
+
+class CustomInvokableClass
+{
+    public function __invoke($value)
+    {
+        return $value.'ModifiedByInvokable';
+    }
+}