diff --git a/src/EventDispatcher/EventSubscribersCollection.php b/src/EventDispatcher/EventSubscribersCollection.php
index 4c6133d..212389d 100644
--- a/src/EventDispatcher/EventSubscribersCollection.php
+++ b/src/EventDispatcher/EventSubscribersCollection.php
@@ -8,9 +8,11 @@
 use RuntimeException;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use WonderNetwork\SlimKernel\ServiceFactory;
+use WonderNetwork\SlimKernel\ServicesBuilder;
 use function DI\decorate;
 
-final readonly class EventSubscribersCollection {
+final readonly class EventSubscribersCollection implements ServiceFactory {
     public static function start(): self {
         return new self([]);
     }
@@ -21,6 +23,10 @@ public static function start(): self {
     public function __construct(private array $subscribers) {
     }
 
+    public function __invoke(ServicesBuilder $builder): iterable {
+        yield from $this->register();
+    }
+
     /**
      * @param class-string<EventSubscriberInterface> ...$subscribers
      */
diff --git a/src/Messenger/WorkerMemoryUsageSubscriber.php b/src/Messenger/WorkerMemoryUsageSubscriber.php
new file mode 100644
index 0000000..6e2513a
--- /dev/null
+++ b/src/Messenger/WorkerMemoryUsageSubscriber.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WonderNetwork\SlimKernel\Messenger;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\Messenger\Event\WorkerRunningEvent;
+use WonderNetwork\SlimKernel\System\RealSystem;
+use WonderNetwork\SlimKernel\System\System;
+
+final class WorkerMemoryUsageSubscriber implements EventSubscriberInterface {
+    private int $memoryUsage;
+    private readonly System $system;
+
+    /**
+     * @return iterable<string,string>
+     */
+    public static function getSubscribedEvents(): iterable {
+        return [
+            WorkerRunningEvent::class => 'onWorkerRunning',
+        ];
+    }
+
+    public function __construct(
+        private readonly LoggerInterface $logger,
+        private readonly int $cutoff = 1024,
+        System $system = null,
+    ) {
+        $this->system = $system ?? new RealSystem();
+        $this->memoryUsage = $this->system->memoryUsage();
+    }
+
+    public function onWorkerRunning(): void {
+        $currentUsage = $this->system->memoryUsage();
+
+        $difference = abs($this->memoryUsage - $currentUsage);
+
+        if ($difference < $this->cutoff) {
+            return;
+        }
+
+        $this->logger->debug(
+            "Memory usage changed: {current} ({sign}{difference})",
+            [
+                'current' => $this->formatBytes($currentUsage),
+                'sign' => ($this->memoryUsage > $currentUsage) ? "-" : "+",
+                'difference' => $this->formatBytes($difference),
+            ],
+        );
+
+        $this->memoryUsage = $currentUsage;
+    }
+
+    private function formatBytes(int $bytes): string {
+        $units = ['B', 'KB', 'MB', 'GB', 'TB'];
+
+        $bytes = max($bytes, 0);
+        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
+        $pow = (int) min($pow, count($units) - 1);
+
+        $bytes /= 1024 ** $pow;
+
+        return sprintf("%s %s", round($bytes, 2), $units[$pow]);
+    }
+}
diff --git a/src/System/RealSystem.php b/src/System/RealSystem.php
new file mode 100644
index 0000000..839b087
--- /dev/null
+++ b/src/System/RealSystem.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WonderNetwork\SlimKernel\System;
+
+final readonly class RealSystem implements System {
+    public function memoryUsage(): int {
+        return memory_get_usage();
+    }
+}
diff --git a/src/System/System.php b/src/System/System.php
new file mode 100644
index 0000000..a4af56c
--- /dev/null
+++ b/src/System/System.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WonderNetwork\SlimKernel\System;
+
+interface System {
+    public function memoryUsage(): int;
+}
diff --git a/tests/ConsoleLogger/ConsoleLoggerTest.php b/tests/ConsoleLogger/ConsoleLoggerTest.php
index 6678d6d..310abd4 100644
--- a/tests/ConsoleLogger/ConsoleLoggerTest.php
+++ b/tests/ConsoleLogger/ConsoleLoggerTest.php
@@ -42,11 +42,12 @@ public function testConsoleLogger(): void {
                         return $logger;
                     },
                     ConsoleHandlerEventSubscriber::class => autowire(),
-                    ...EventSubscribersCollection::start()
-                        ->add(ConsoleHandlerEventSubscriber::class)
-                        ->register(),
                 ],
             )
+            ->register(
+                EventSubscribersCollection::start()
+                    ->add(ConsoleHandlerEventSubscriber::class),
+            )
             ->register(
                 new SymfonyConsoleServiceFactory(
                     path: '/src/*Command.php',
diff --git a/tests/Messenger/WorkerMemoryUsageSubscriberTest.php b/tests/Messenger/WorkerMemoryUsageSubscriberTest.php
new file mode 100644
index 0000000..677ebd5
--- /dev/null
+++ b/tests/Messenger/WorkerMemoryUsageSubscriberTest.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WonderNetwork\SlimKernel\Messenger;
+
+use Monolog\Handler\TestHandler;
+use Monolog\Logger;
+use PHPUnit\Framework\TestCase;
+use WonderNetwork\SlimKernel\System\FakeSystem;
+
+final class WorkerMemoryUsageSubscriberTest extends TestCase {
+    public function testReportsAboveCutoff(): void {
+        $buffer = new TestHandler();
+        $logger = new Logger('some');
+        $logger->pushHandler($buffer);
+
+        $system = new FakeSystem();
+
+        $sut = new WorkerMemoryUsageSubscriber(
+            logger: $logger,
+            cutoff: 10 * 1024,
+            system: $system,
+        );
+        $sut->onWorkerRunning();
+        self::assertEmpty($buffer->getRecords());
+
+        $system->setMemoryUsage(10 * 1024 - 1);
+        $sut->onWorkerRunning();
+        self::assertCount(0, $buffer->getRecords());
+
+        $system->setMemoryUsage(10 * 1024);
+        $sut->onWorkerRunning();
+        self::assertCount(1, $buffer->getRecords());
+        self::assertSame([
+            'current' => '10 KB',
+            'sign' => '+',
+            'difference' => '10 KB',
+        ], $buffer->getRecords()[0]->context);
+
+        $sut->onWorkerRunning();
+        $system->setMemoryUsage(12 * 1024);
+        $sut->onWorkerRunning();
+        self::assertCount(1, $buffer->getRecords());
+    }
+}
diff --git a/tests/System/FakeSystem.php b/tests/System/FakeSystem.php
new file mode 100644
index 0000000..3562efd
--- /dev/null
+++ b/tests/System/FakeSystem.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WonderNetwork\SlimKernel\System;
+
+final class FakeSystem implements System {
+    private int $memoryUsage = 0;
+
+    public function setMemoryUsage(int $memoryUsage): void {
+        $this->memoryUsage = $memoryUsage;
+    }
+
+    public function memoryUsage(): int {
+        return $this->memoryUsage;
+    }
+}