diff --git a/docs/pages/subscription.md b/docs/pages/subscription.md
index 1f0c9d764..d496fa233 100644
--- a/docs/pages/subscription.md
+++ b/docs/pages/subscription.md
@@ -567,6 +567,32 @@ $subscriptionEngine = new DefaultSubscriptionEngine(
     $retryStrategy,
 );
 ```
+### Catchup Subscription Engine
+
+If aggregates are used in the processors and new events are generated there,
+then they are not part of the current subscription engine run and will only be processed during the next run or boot.
+This is usually not a problem in dev or prod environment because a worker is used
+and these events will be processed at some point. But in testing it is not so easy.
+For this reason, we have the `CatchupSubscriptionEngine`.
+
+```php
+use Patchlevel\EventSourcing\Store\Store;
+use Patchlevel\EventSourcing\Subscription\Engine\CatchupSubscriptionEngine;
+use Patchlevel\EventSourcing\Subscription\Engine\SubscriptionEngine;
+
+/**
+ * @var Store $eventStore
+ * @var SubscriptionEngine $subscriptionStore
+ */
+$catchupSubscriptionEngine = new CatchupSubscriptionEngine(
+    $eventStore,
+    $subscriptionEngine,
+);
+```
+!!! tip
+
+    You can use the `CatchupSubscriptionEngine` in your tests to process the events immediately.
+    
 ## Usage
 
 The Subscription Engine has a few methods needed to use it effectively.
diff --git a/src/Subscription/Engine/CatchUpSubscriptionEngine.php b/src/Subscription/Engine/CatchUpSubscriptionEngine.php
new file mode 100644
index 000000000..26f387780
--- /dev/null
+++ b/src/Subscription/Engine/CatchUpSubscriptionEngine.php
@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Subscription\Engine;
+
+use Patchlevel\EventSourcing\Store\Store;
+use Patchlevel\EventSourcing\Subscription\Subscription;
+
+use const PHP_INT_MAX;
+
+final class CatchUpSubscriptionEngine implements SubscriptionEngine
+{
+    public function __construct(
+        private readonly SubscriptionEngine $parent,
+        private readonly Store $store,
+        private readonly int $limit = PHP_INT_MAX,
+    ) {
+    }
+
+    public function setup(SubscriptionEngineCriteria|null $criteria = null, bool $skipBooting = false): void
+    {
+        $this->parent->setup($criteria, $skipBooting);
+    }
+
+    public function boot(SubscriptionEngineCriteria|null $criteria = null, int|null $limit = null): void
+    {
+        for ($i = 0; $i < $this->limit; $i++) {
+            $current = $this->store->count();
+            $this->parent->boot($criteria, $limit);
+            if ($current === $this->store->count()) {
+                break;
+            }
+        }
+    }
+
+    public function run(SubscriptionEngineCriteria|null $criteria = null, int|null $limit = null): void
+    {
+        for ($i = 0; $i < $this->limit; $i++) {
+            $current = $this->store->count();
+            $this->parent->run($criteria, $limit);
+            if ($current === $this->store->count()) {
+                break;
+            }
+        }
+    }
+
+    public function teardown(SubscriptionEngineCriteria|null $criteria = null): void
+    {
+        $this->parent->teardown($criteria);
+    }
+
+    public function remove(SubscriptionEngineCriteria|null $criteria = null): void
+    {
+        $this->parent->remove($criteria);
+    }
+
+    public function reactivate(SubscriptionEngineCriteria|null $criteria = null): void
+    {
+        $this->parent->reactivate($criteria);
+    }
+
+    public function pause(SubscriptionEngineCriteria|null $criteria = null): void
+    {
+        $this->parent->pause($criteria);
+    }
+
+    /** @return list<Subscription> */
+    public function subscriptions(SubscriptionEngineCriteria|null $criteria = null): array
+    {
+        return $this->parent->subscriptions($criteria);
+    }
+}
diff --git a/tests/Unit/Subscription/Engine/CatchUpSubscriptionEngineTest.php b/tests/Unit/Subscription/Engine/CatchUpSubscriptionEngineTest.php
new file mode 100644
index 000000000..fd454376f
--- /dev/null
+++ b/tests/Unit/Subscription/Engine/CatchUpSubscriptionEngineTest.php
@@ -0,0 +1,179 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Subscription\Engine;
+
+use Patchlevel\EventSourcing\Store\Store;
+use Patchlevel\EventSourcing\Subscription\Engine\CatchUpSubscriptionEngine;
+use Patchlevel\EventSourcing\Subscription\Engine\SubscriptionEngine;
+use Patchlevel\EventSourcing\Subscription\Engine\SubscriptionEngineCriteria;
+use Patchlevel\EventSourcing\Subscription\Subscription;
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+
+/** @covers \Patchlevel\EventSourcing\Subscription\Engine\CatchUpSubscriptionEngine */
+final class CatchUpSubscriptionEngineTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testSetup(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $parent->setup($criteria, true)->shouldBeCalled();
+        $engine->setup($criteria, true);
+    }
+
+    public function testBootFinished(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42)->shouldBeCalledTimes(2);
+
+        $parent->run($criteria, 42)->shouldBeCalledOnce();
+        $engine->run($criteria, 42);
+    }
+
+    public function testBootSecondTime(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42, 43, 43);
+
+        $parent->run($criteria, 42)->shouldBeCalledTimes(2);
+        $engine->run($criteria, 42);
+    }
+
+    public function testBootLimit(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal(), 2);
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42, 43, 44);
+
+        $parent->run($criteria, 42)->shouldBeCalledTimes(2);
+        $engine->run($criteria, 42);
+    }
+
+    public function testRunFinished(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42)->shouldBeCalledTimes(2);
+
+        $parent->run($criteria, 42)->shouldBeCalledOnce();
+        $engine->run($criteria, 42);
+    }
+
+    public function testRunSecondTime(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42, 43, 43);
+
+        $parent->run($criteria, 42)->shouldBeCalledTimes(2);
+        $engine->run($criteria, 42);
+    }
+
+    public function testRunLimit(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal(), 2);
+        $criteria = new SubscriptionEngineCriteria();
+
+        $store->count()->willReturn(42, 43, 44);
+
+        $parent->run($criteria, 42)->shouldBeCalledTimes(2);
+        $engine->run($criteria, 42);
+    }
+
+    public function testTeardown(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $parent->teardown($criteria)->shouldBeCalled();
+        $engine->teardown($criteria);
+    }
+
+    public function testRemove(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $parent->remove($criteria)->shouldBeCalled();
+        $engine->remove($criteria);
+    }
+
+    public function testReactivate(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $parent->reactivate($criteria)->shouldBeCalled();
+        $engine->reactivate($criteria);
+    }
+
+    public function testPause(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $parent->pause($criteria)->shouldBeCalled();
+        $engine->pause($criteria);
+    }
+
+    public function testSubscriptions(): void
+    {
+        $parent = $this->prophesize(SubscriptionEngine::class);
+        $store = $this->prophesize(Store::class);
+
+        $engine = new CatchUpSubscriptionEngine($parent->reveal(), $store->reveal());
+        $criteria = new SubscriptionEngineCriteria();
+
+        $expectedSubscriptions = [new Subscription('foo')];
+
+        $parent->subscriptions($criteria)->willReturn($expectedSubscriptions)->shouldBeCalled();
+        $subscriptions = $engine->subscriptions($criteria);
+
+        self::assertEquals($expectedSubscriptions, $subscriptions);
+    }
+}