diff --git a/composer.json b/composer.json
index d1c72f9..574e4af 100644
--- a/composer.json
+++ b/composer.json
@@ -41,6 +41,7 @@
         "symfony/string": " 6.1.*",
         "symfony/translation": " 6.1.*",
         "symfony/twig-bundle": " 6.1.*",
+        "symfony/uid": " 6.1.*",
         "symfony/validator": " 6.1.*",
         "symfony/web-link": " 6.1.*",
         "symfony/yaml": " 6.1.*",
diff --git a/composer.lock b/composer.lock
index 50f7c54..f5719d8 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "3782904a5950ea216badb0d03761a762",
+    "content-hash": "1bfc4cd53ff6415f1246ad7cbdab8353",
     "packages": [
         {
             "name": "composer/package-versions-deprecated",
@@ -6299,6 +6299,88 @@
             ],
             "time": "2022-05-10T07:21:04+00:00"
         },
+        {
+            "name": "symfony/polyfill-uuid",
+            "version": "v1.27.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-uuid.git",
+                "reference": "f3cf1a645c2734236ed1e2e671e273eeb3586166"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-uuid/zipball/f3cf1a645c2734236ed1e2e671e273eeb3586166",
+                "reference": "f3cf1a645c2734236ed1e2e671e273eeb3586166",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1"
+            },
+            "provide": {
+                "ext-uuid": "*"
+            },
+            "suggest": {
+                "ext-uuid": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "1.27-dev"
+                },
+                "thanks": {
+                    "name": "symfony/polyfill",
+                    "url": "https://github.com/symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Polyfill\\Uuid\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Grégoire Pineau",
+                    "email": "lyrixx@lyrixx.info"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for uuid functions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "uuid"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-uuid/tree/v1.27.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2022-11-03T14:55:06+00:00"
+        },
         {
             "name": "symfony/process",
             "version": "v6.1.3",
@@ -7821,6 +7903,80 @@
             ],
             "time": "2022-05-27T16:55:36+00:00"
         },
+        {
+            "name": "symfony/uid",
+            "version": "v6.1.11",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/uid.git",
+                "reference": "7c53913df24517eb5e0fab4caf294e84fcecc277"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/uid/zipball/7c53913df24517eb5e0fab4caf294e84fcecc277",
+                "reference": "7c53913df24517eb5e0fab4caf294e84fcecc277",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.1",
+                "symfony/polyfill-uuid": "^1.15"
+            },
+            "require-dev": {
+                "symfony/console": "^5.4|^6.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\Uid\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Grégoire Pineau",
+                    "email": "lyrixx@lyrixx.info"
+                },
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Provides an object-oriented API to generate and represent UIDs",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "UID",
+                "ulid",
+                "uuid"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/uid/tree/v6.1.11"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2023-01-01T08:36:55+00:00"
+        },
         {
             "name": "symfony/validator",
             "version": "v6.1.5",
diff --git a/config/doctrine/orm/Dinosaur.orm.xml b/config/doctrine/orm/Dinosaur.orm.xml
index e1f769d..eec174e 100644
--- a/config/doctrine/orm/Dinosaur.orm.xml
+++ b/config/doctrine/orm/Dinosaur.orm.xml
@@ -10,9 +10,7 @@
         table="dinosaur"
     >
 
-        <id name="id" type="integer" column="id">
-            <generator strategy="AUTO"/>
-        </id>
+        <id name="id" type="uuid" />
 
         <field name="name" column="name" type="string" length="255" nullable="false" unique="false" />
         <field name="gender" column="gender" type="string" length="255" nullable="false" unique="false" />
diff --git a/config/doctrine/orm/Species.orm.xml b/config/doctrine/orm/Species.orm.xml
index 100370d..dbaa335 100644
--- a/config/doctrine/orm/Species.orm.xml
+++ b/config/doctrine/orm/Species.orm.xml
@@ -10,9 +10,7 @@
         table="species"
     >
 
-        <id name="id" type="integer" column="id">
-            <generator strategy="AUTO"/>
-        </id>
+        <id name="id" type="uuid" />
 
         <field name="name" column="name" type="string" length="255" nullable="false" unique="true" />
         <field name="habitats" column="habitats" type="simple_array" nullable="false" unique="false" />
diff --git a/config/packages/messenger.yaml b/config/packages/messenger.yaml
index 66e6802..697a115 100644
--- a/config/packages/messenger.yaml
+++ b/config/packages/messenger.yaml
@@ -28,4 +28,4 @@ framework:
       routing:
           'App\Message\Food\Consume': async_low_priority
           'App\Message\Food\Refill': async_high_priority
-          'App\Event\Event': async_low_priority
+          'App\Event\AsyncLowPriorityEvent': async_low_priority
diff --git a/migrations/Version20230217084031.php b/migrations/Version20230217084031.php
new file mode 100644
index 0000000..7e08774
--- /dev/null
+++ b/migrations/Version20230217084031.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20230217084031 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Migrating integer ids to UUIDs';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE dinosaur DROP FOREIGN KEY FK_DAEDC56EB2A1D860');
+        $this->addSql('ALTER TABLE dinosaur CHANGE id id BINARY(16) NOT NULL COMMENT \'(DC2Type:uuid)\', CHANGE species_id species_id BINARY(16) DEFAULT NULL COMMENT \'(DC2Type:uuid)\'');
+        $this->addSql('ALTER TABLE species CHANGE id id BINARY(16) NOT NULL COMMENT \'(DC2Type:uuid)\'');
+        $this->addSql('ALTER TABLE dinosaur ADD CONSTRAINT FK_DAEDC56EB2A1D860 FOREIGN KEY (species_id) REFERENCES species (id)');
+    }
+
+    public function down(Schema $schema): void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE dinosaur DROP FOREIGN KEY FK_DAEDC56EB2A1D860');
+        $this->addSql('ALTER TABLE dinosaur CHANGE id id INT AUTO_INCREMENT NOT NULL, CHANGE species_id species_id INT DEFAULT NULL');
+        $this->addSql('ALTER TABLE species CHANGE id id INT AUTO_INCREMENT NOT NULL');
+        $this->addSql('ALTER TABLE dinosaur ADD CONSTRAINT FK_DAEDC56EB2A1D860 FOREIGN KEY (species_id) REFERENCES species (id)');
+    }
+}
diff --git a/src/Command/ConsumeCommand.php b/src/Command/ConsumeCommand.php
index 63d4a03..3c55025 100644
--- a/src/Command/ConsumeCommand.php
+++ b/src/Command/ConsumeCommand.php
@@ -39,7 +39,10 @@ protected function execute(InputInterface $input, OutputInterface $output)
 
             $dinosaur = $dinosaurs[$randomDinoKey];
 
-            $consumeMessage = new Consume($dinosaur->getId(), $dinosaur->getName());
+            $consumeMessage = new Consume(
+                $dinosaur->getId()->toRfc4122(),
+                $dinosaur->getName()
+            );
 
             $this->bus->dispatch($consumeMessage);
         }
diff --git a/src/Controller/DinosaursController.php b/src/Controller/DinosaursController.php
index da10a5f..48dff13 100644
--- a/src/Controller/DinosaursController.php
+++ b/src/Controller/DinosaursController.php
@@ -50,7 +50,7 @@ public function list(Request $request, ManagerRegistry $doctrine): Response
     #[Route(
         '/dinosaurs/{id}',
         name: 'app_single_dinosaur',
-        requirements: ['id' => '\d+']
+        requirements: ['id' => '^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$']
     )]
     public function single(string $id, ManagerRegistry $doctrine): Response
     {
@@ -71,7 +71,7 @@ public function single(string $id, ManagerRegistry $doctrine): Response
     }
 
     #[Route('/dinosaurs/create', name: 'app_create_dinosaur')]
-    public function create(Request $request, ManagerRegistry $doctrine): Response
+    public function create(Request $request): Response
     {
         $form = $this->createForm(DinosaurType::class);
 
@@ -105,9 +105,9 @@ public function create(Request $request, ManagerRegistry $doctrine): Response
     #[Route(
         '/dinosaurs/{id}/edit',
         name: 'app_edit_dinosaur',
-        requirements: ['id' => '\d+']
+        requirements: ['id' => '^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$']
     )]
-    public function edit(Request $request, int $id, ManagerRegistry $doctrine): Response
+    public function edit(Request $request, string $id, ManagerRegistry $doctrine): Response
     {
         $dinosaur = $doctrine
             ->getRepository(Dinosaur::class)
@@ -149,9 +149,9 @@ public function edit(Request $request, int $id, ManagerRegistry $doctrine): Resp
     #[Route(
         '/dinosaurs/{id}/remove',
         name: 'app_remove_dinosaur',
-        requirements: ['id' => '\d+']
+        requirements: ['id' => '^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$']
     )]
-    public function remove(int $id): Response
+    public function remove(string $id): Response
     {
         $this->bus->dispatch(new Delete($id));
 
diff --git a/src/Controller/SpeciesController.php b/src/Controller/SpeciesController.php
index 9f32c39..9a54c46 100644
--- a/src/Controller/SpeciesController.php
+++ b/src/Controller/SpeciesController.php
@@ -66,9 +66,9 @@ public function create(Request $request, ManagerRegistry $doctrine): Response
     #[Route(
         '/species/{id}/edit',
         name: 'app_edit_species',
-        requirements: ['id' => '\d+']
+        requirements: ['id' => '^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$']
     )]
-    public function edit(Request $request, int $id, ManagerRegistry $doctrine): Response
+    public function edit(Request $request, string $id, ManagerRegistry $doctrine): Response
     {
         $species = $doctrine
             ->getRepository(Species::class)
@@ -108,9 +108,9 @@ public function edit(Request $request, int $id, ManagerRegistry $doctrine): Resp
     #[Route(
         '/species/{id}/remove',
         name: 'app_remove_species',
-        requirements: ['id' => '\d+']
+        requirements: ['id' => '^[0-9a-fA-F]{8}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{4}\b-[0-9a-fA-F]{12}$']
     )]
-    public function remove(int $id): Response
+    public function remove(string $id): Response
     {
         $this->bus->dispatch(new Delete($id));
 
diff --git a/src/Entity/Dinosaur.php b/src/Entity/Dinosaur.php
index 74b7bea..43643e4 100644
--- a/src/Entity/Dinosaur.php
+++ b/src/Entity/Dinosaur.php
@@ -2,9 +2,11 @@
 
 namespace App\Entity;
 
+use Symfony\Component\Uid\Uuid;
+
 class Dinosaur
 {
-    private int $id;
+    private ?Uuid $id;
     private string $name;
     private string $gender;
     private Species $species;
@@ -18,8 +20,10 @@ public function __construct(
         Species $species,
         int $age,
         string $eyesColor,
-        Park $park
+        Park $park,
+        ?Uuid $id = null
     ) {
+        $this->id = $id ?? Uuid::v4();
         $this->name = $name;
         $this->gender = $gender;
         $this->species = $species;
@@ -28,11 +32,16 @@ public function __construct(
         $this->park = $park;
     }
 
-    public function getId(): int
+    public function getId(): ?Uuid
     {
         return $this->id;
     }
 
+    public function setId(?Uuid $id): void
+    {
+        $this->id = $id;
+    }
+
     public function getName(): string
     {
         return $this->name;
diff --git a/src/Entity/Species.php b/src/Entity/Species.php
index 3a958fd..c49d2a3 100644
--- a/src/Entity/Species.php
+++ b/src/Entity/Species.php
@@ -4,10 +4,11 @@
 
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
+use Symfony\Component\Uid\Uuid;
 
 class Species
 {
-    private int $id;
+    private ?Uuid $id;
     private string $name;
     private array $habitats;
     private string $feeding;
@@ -17,18 +18,25 @@ public function __construct(
         string $name,
         array $habitats,
         string $feeding,
+        ?Uuid $id = null
     ) {
+        $this->id = $id ?? Uuid::v4();
         $this->name = $name;
         $this->habitats = $habitats;
         $this->feeding = $feeding;
         $this->dinosaurs = new ArrayCollection();
     }
 
-    public function getId(): int
+    public function getId(): ?Uuid
     {
         return $this->id;
     }
 
+    public function setId(?Uuid $id): void
+    {
+        $this->id = $id;
+    }
+
     public function getName(): string
     {
         return $this->name;
diff --git a/src/Event/AbstractEvent.php b/src/Event/AbstractEvent.php
index 4408c2e..be3b76e 100644
--- a/src/Event/AbstractEvent.php
+++ b/src/Event/AbstractEvent.php
@@ -4,14 +4,14 @@
 
 namespace App\Event;
 
-class AbstractEvent implements Event
+class AbstractEvent
 {
     public function __construct(
-        private int $id
+        private string $id
     ) {
     }
 
-    public function getAggregateRootId(): int
+    public function getId(): string
     {
         return $this->id;
     }
diff --git a/src/Event/AsyncLowPriorityEvent.php b/src/Event/AsyncLowPriorityEvent.php
new file mode 100644
index 0000000..e9ba284
--- /dev/null
+++ b/src/Event/AsyncLowPriorityEvent.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Event;
+
+interface AsyncLowPriorityEvent
+{
+}
diff --git a/src/Event/Dinosaur/HasBeenCreated.php b/src/Event/Dinosaur/HasBeenCreated.php
index 08ee4ba..a14552a 100644
--- a/src/Event/Dinosaur/HasBeenCreated.php
+++ b/src/Event/Dinosaur/HasBeenCreated.php
@@ -5,7 +5,8 @@
 namespace App\Event\Dinosaur;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenCreated extends AbstractEvent
+class HasBeenCreated extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Dinosaur/HasBeenDeleted.php b/src/Event/Dinosaur/HasBeenDeleted.php
index 9c396e4..4bdd532 100644
--- a/src/Event/Dinosaur/HasBeenDeleted.php
+++ b/src/Event/Dinosaur/HasBeenDeleted.php
@@ -5,7 +5,8 @@
 namespace App\Event\Dinosaur;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenDeleted extends AbstractEvent
+class HasBeenDeleted extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Dinosaur/HasBeenUpdated.php b/src/Event/Dinosaur/HasBeenUpdated.php
index ea33f31..0410c89 100644
--- a/src/Event/Dinosaur/HasBeenUpdated.php
+++ b/src/Event/Dinosaur/HasBeenUpdated.php
@@ -5,7 +5,8 @@
 namespace App\Event\Dinosaur;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenUpdated extends AbstractEvent
+class HasBeenUpdated extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Event.php b/src/Event/Event.php
deleted file mode 100644
index a15b48e..0000000
--- a/src/Event/Event.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace App\Event;
-
-interface Event
-{
-    public function getAggregateRootId(): int;
-}
diff --git a/src/Event/Food/HasBeenConsumed.php b/src/Event/Food/HasBeenConsumed.php
index 22d464d..9c3eaa0 100644
--- a/src/Event/Food/HasBeenConsumed.php
+++ b/src/Event/Food/HasBeenConsumed.php
@@ -5,7 +5,8 @@
 namespace App\Event\Food;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenConsumed extends AbstractEvent
+class HasBeenConsumed extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Food/HasBeenRefilled.php b/src/Event/Food/HasBeenRefilled.php
index 20b95a5..c53b0f3 100644
--- a/src/Event/Food/HasBeenRefilled.php
+++ b/src/Event/Food/HasBeenRefilled.php
@@ -5,7 +5,8 @@
 namespace App\Event\AbstractEvent;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenRefilled extends AbstractEvent
+class HasBeenRefilled extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Species/HasBeenCreated.php b/src/Event/Species/HasBeenCreated.php
index 34c2e6d..c0d6a18 100644
--- a/src/Event/Species/HasBeenCreated.php
+++ b/src/Event/Species/HasBeenCreated.php
@@ -5,7 +5,8 @@
 namespace App\Event\Species;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenCreated extends AbstractEvent
+class HasBeenCreated extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Species/HasBeenDeleted.php b/src/Event/Species/HasBeenDeleted.php
index c474107..221e66b 100644
--- a/src/Event/Species/HasBeenDeleted.php
+++ b/src/Event/Species/HasBeenDeleted.php
@@ -5,7 +5,8 @@
 namespace App\Event\Species;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenDeleted extends AbstractEvent
+class HasBeenDeleted extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/Event/Species/HasBeenUpdated.php b/src/Event/Species/HasBeenUpdated.php
index c7ad128..2b0a385 100644
--- a/src/Event/Species/HasBeenUpdated.php
+++ b/src/Event/Species/HasBeenUpdated.php
@@ -5,7 +5,8 @@
 namespace App\Event\Species;
 
 use App\Event\AbstractEvent;
+use App\Event\AsyncLowPriorityEvent;
 
-class HasBeenUpdated extends AbstractEvent
+class HasBeenUpdated extends AbstractEvent implements AsyncLowPriorityEvent
 {
 }
diff --git a/src/EventHandler/Dinosaur/DeleteDinosaurSummary.php b/src/EventHandler/Dinosaur/DeleteDinosaurSummary.php
index 34e0e19..a0eff9e 100644
--- a/src/EventHandler/Dinosaur/DeleteDinosaurSummary.php
+++ b/src/EventHandler/Dinosaur/DeleteDinosaurSummary.php
@@ -18,6 +18,6 @@ public function __construct(
     #[AsMessageHandler]
     public function handleDinosaurHasBeenDeleted(DinosaurHasBeenDeleted $event): void
     {
-        $this->indexer->delete($event->getAggregateRootId());
+        $this->indexer->delete($event->getId());
     }
 }
diff --git a/src/EventHandler/Dinosaur/UpsertDinosaurSummary.php b/src/EventHandler/Dinosaur/UpsertDinosaurSummary.php
index d161064..3500455 100644
--- a/src/EventHandler/Dinosaur/UpsertDinosaurSummary.php
+++ b/src/EventHandler/Dinosaur/UpsertDinosaurSummary.php
@@ -26,31 +26,31 @@ public function __construct(
     #[AsMessageHandler]
     public function handleDinosaurHasBeenCreated(DinosaurHasBeenCreated $event): void
     {
-        $this->updateSummaryByDinosaur($event->getAggregateRootId());
+        $this->updateSummaryByDinosaur($event->getId());
     }
 
     #[AsMessageHandler]
     public function handleDinosaurHasBeenUpdated(DinosaurHasBeenUpdated $event): void
     {
-        $this->updateSummaryByDinosaur($event->getAggregateRootId());
+        $this->updateSummaryByDinosaur($event->getId());
     }
 
     #[AsMessageHandler]
     public function handleFoodHasBeenConsumed(HasBeenConsumed $event): void
     {
-        $this->updateSummariesByPark($event->getAggregateRootId());
+        $this->updateSummariesByPark((int) $event->getId());
     }
 
     #[AsMessageHandler]
     public function handleFoodHasBeenRefilled(HasBeenRefilled $event): void
     {
-        $this->updateSummariesByPark($event->getAggregateRootId());
+        $this->updateSummariesByPark((int) $event->getId());
     }
 
     #[AsMessageHandler]
     public function handleSpeciesHasBeenUpdated(SpeciesHasBeenUpdated $event): void
     {
-        $speciesId = $event->getAggregateRootId();
+        $speciesId = $event->getId();
 
         $species = $this ->speciesRepository->find($speciesId);
 
@@ -68,7 +68,7 @@ public function handleSpeciesHasBeenUpdated(SpeciesHasBeenUpdated $event): void
         }
     }
 
-    private function updateSummaryByDinosaur(int $dinosaurId): void
+    private function updateSummaryByDinosaur(string $dinosaurId): void
     {
         $dinosaur = $this->dinosaurRepository->find($dinosaurId);
 
diff --git a/src/EventListener/WorkerListener.php b/src/EventListener/WorkerListener.php
index 5a82e5e..088f6a9 100644
--- a/src/EventListener/WorkerListener.php
+++ b/src/EventListener/WorkerListener.php
@@ -59,6 +59,10 @@ public function onWorkerMessageHandledEvent(WorkerMessageHandledEvent $event)
 
         $handledStamp = $envelope->last(HandledStamp::class);
 
+        if (null === $handledStamp) {
+            return;
+        }
+
         $handlerName = $handledStamp->getHandlerName();
 
         $message = $envelope->getMessage();
diff --git a/src/Form/Type/DinosaurType.php b/src/Form/Type/DinosaurType.php
index 919a461..4a617b0 100644
--- a/src/Form/Type/DinosaurType.php
+++ b/src/Form/Type/DinosaurType.php
@@ -8,7 +8,6 @@
 use Symfony\Bridge\Doctrine\Form\Type\EntityType;
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\Extension\Core\Type\ColorType;
-use Symfony\Component\Form\Extension\Core\Type\HiddenType;
 use Symfony\Component\Form\Extension\Core\Type\NumberType;
 use Symfony\Component\Form\Extension\Core\Type\SubmitType;
 use Symfony\Component\Form\Extension\Core\Type\TextType;
diff --git a/src/Indexer.php b/src/Indexer.php
index 80be302..f115818 100644
--- a/src/Indexer.php
+++ b/src/Indexer.php
@@ -37,7 +37,7 @@ public function indexFromDinosaur(Dinosaur $dinosaur): void
         ]);
     }
 
-    public function delete(int $id)
+    public function delete(string $id)
     {
         $this->client->delete([
             'index' => self::INDEX_NAME,
diff --git a/src/Message/Dinosaur/Create.php b/src/Message/Dinosaur/Create.php
index 5ccc485..7190c94 100644
--- a/src/Message/Dinosaur/Create.php
+++ b/src/Message/Dinosaur/Create.php
@@ -9,7 +9,7 @@ public function __construct(
         public readonly string $gender,
         public readonly string $eyesColor,
         public readonly int $age,
-        public readonly int $speciesId,
+        public readonly string $speciesId,
         public readonly int $parkId,
     ) {
     }
diff --git a/src/Message/Dinosaur/Delete.php b/src/Message/Dinosaur/Delete.php
index 4bbd29d..941dfc2 100644
--- a/src/Message/Dinosaur/Delete.php
+++ b/src/Message/Dinosaur/Delete.php
@@ -5,7 +5,7 @@
 class Delete
 {
     public function __construct(
-        public readonly int $id
+        public readonly string $id
     ) {
     }
 }
diff --git a/src/Message/Dinosaur/Edit.php b/src/Message/Dinosaur/Edit.php
index fb6102a..88e2c9c 100644
--- a/src/Message/Dinosaur/Edit.php
+++ b/src/Message/Dinosaur/Edit.php
@@ -5,12 +5,12 @@
 class Edit
 {
     public function __construct(
-        public readonly int $id,
+        public readonly string $id,
         public readonly string $name,
         public readonly string $gender,
         public readonly string $eyesColor,
         public readonly int $age,
-        public readonly int $speciesId
+        public readonly string $speciesId
     ) {
     }
 }
diff --git a/src/Message/Food/Consume.php b/src/Message/Food/Consume.php
index 336f2ac..8cb8dda 100644
--- a/src/Message/Food/Consume.php
+++ b/src/Message/Food/Consume.php
@@ -9,7 +9,7 @@
 class Consume implements Lockable
 {
     public function __construct(
-        public readonly int $dinosaurId,
+        public readonly string $dinosaurId,
         public readonly string $dinosaurName
     ) {
     }
diff --git a/src/Message/Species/Delete.php b/src/Message/Species/Delete.php
index b0b40ef..578beae 100644
--- a/src/Message/Species/Delete.php
+++ b/src/Message/Species/Delete.php
@@ -5,7 +5,7 @@
 class Delete
 {
     public function __construct(
-        public readonly int $id
+        public readonly string $id
     ) {
     }
 }
diff --git a/src/Message/Species/Edit.php b/src/Message/Species/Edit.php
index 911c931..5fb840c 100644
--- a/src/Message/Species/Edit.php
+++ b/src/Message/Species/Edit.php
@@ -5,7 +5,7 @@
 class Edit
 {
     public function __construct(
-        public readonly int $id,
+        public readonly string $id,
         public readonly string $name,
         public readonly string $feeding,
         public readonly array $habitats
diff --git a/src/MessageHandler/Dinosaur/Create.php b/src/MessageHandler/Dinosaur/Create.php
index 209a671..fa1da30 100644
--- a/src/MessageHandler/Dinosaur/Create.php
+++ b/src/MessageHandler/Dinosaur/Create.php
@@ -47,15 +47,13 @@ public function __invoke(CreateMessage $message)
 
         $this->dinosaurRepository->add($dino);
 
-        $id = $this->dinosaurRepository->findNextId();
-
-        $envelop = new Envelope(new HasBeenCreated($id));
+        $envelop = new Envelope(new HasBeenCreated($dino->getId()->toRfc4122()));
 
         $this
             ->eventBus
             ->dispatch($envelop->with(new DispatchAfterCurrentBusStamp()))
         ;
 
-        return new CreateMessageResult($id);
+        return new CreateMessageResult($dino->getId()->toRfc4122());
     }
 }
diff --git a/src/MessageHandler/Dinosaur/Edit.php b/src/MessageHandler/Dinosaur/Edit.php
index fba67d5..aa2862a 100644
--- a/src/MessageHandler/Dinosaur/Edit.php
+++ b/src/MessageHandler/Dinosaur/Edit.php
@@ -2,12 +2,10 @@
 
 namespace App\MessageHandler\Dinosaur;
 
-use App\Entity\Dinosaur;
-use App\Entity\Species;
 use App\Event\Dinosaur\HasBeenUpdated;
 use App\Message\Dinosaur\Edit as EditMessage;
-use App\MessageResults\Dinosaur\Edit as EditOutput;
-use Doctrine\ORM\EntityManagerInterface;
+use App\Repository\DinosaurRepository;
+use App\Repository\SpeciesRepository;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\Messenger\Attribute\AsMessageHandler;
 use Symfony\Component\Messenger\Envelope;
@@ -19,20 +17,18 @@ final class Edit
 {
     public function __construct(
         private MessageBusInterface $eventBus,
-        private EntityManagerInterface $entityManager
+        private DinosaurRepository $dinosaurRepository,
+        private SpeciesRepository $speciesRepository,
     ) {
     }
 
     public function __invoke(EditMessage $message)
     {
-        $dinosaurRepository = $this->entityManager->getRepository(Dinosaur::class);
-        $speciesRepository = $this->entityManager->getRepository(Species::class);
-
-        if (!$dinosaur = $dinosaurRepository->find($message->id)) {
+        if (!$dinosaur = $this->dinosaurRepository->find($message->id)) {
             throw new NotFoundHttpException("Dinosaur with id {$message->id} not found");
         }
 
-        if (!$species = $speciesRepository->find($message->speciesId)) {
+        if (!$species = $this->speciesRepository->find($message->speciesId)) {
             throw new NotFoundHttpException("Species with id {$message->id} not found");
         }
 
@@ -41,7 +37,7 @@ public function __invoke(EditMessage $message)
         $dinosaur->setAge($message->age);
         $dinosaur->setSpecies($species);
 
-        $envelop = new Envelope(new HasBeenUpdated($dinosaur->getId()));
+        $envelop = new Envelope(new HasBeenUpdated($dinosaur->getId()->toRfc4122()));
 
         $this
             ->eventBus
diff --git a/src/MessageHandler/Food/Consume.php b/src/MessageHandler/Food/Consume.php
index ee83770..39912d4 100644
--- a/src/MessageHandler/Food/Consume.php
+++ b/src/MessageHandler/Food/Consume.php
@@ -54,7 +54,7 @@ public function __invoke(FoodConsume $message)
 
         $park->setFoodAmount($park->getFoodAmount() - $consumedAmout);
 
-        $envelop = new Envelope(new HasBeenConsumed($park->getId()));
+        $envelop = new Envelope(new HasBeenConsumed((string) $park->getId()));
 
         $this
             ->eventBus
diff --git a/src/MessageHandler/Food/Refill.php b/src/MessageHandler/Food/Refill.php
index 952c546..d5772a2 100644
--- a/src/MessageHandler/Food/Refill.php
+++ b/src/MessageHandler/Food/Refill.php
@@ -43,7 +43,7 @@ public function __invoke(FoodRefill $refill)
             $park->setFoodAmount(100);
         }
 
-        $envelop = new Envelope(new HasBeenRefilled($park->getId()));
+        $envelop = new Envelope(new HasBeenRefilled((string) $park->getId()));
 
         $this
             ->eventBus
diff --git a/src/MessageHandler/Species/Create.php b/src/MessageHandler/Species/Create.php
index a4f7db1..f4a426b 100644
--- a/src/MessageHandler/Species/Create.php
+++ b/src/MessageHandler/Species/Create.php
@@ -7,11 +7,11 @@
 use App\Message\Species\Create as CreateMessage;
 use App\MessageResults\Species\Create as CreateMessageResult;
 use App\Repository\SpeciesRepository;
-use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Component\Messenger\Attribute\AsMessageHandler;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Messenger\Stamp\DispatchAfterCurrentBusStamp;
+use Symfony\Component\Uid\Uuid;
 
 #[AsMessageHandler]
 final class Create
@@ -30,17 +30,17 @@ public function __invoke(CreateMessage $message): CreateMessageResult
             feeding: $message->feeding
         );
 
-        $this->speciesRepository->persist($species);
+        $this->speciesRepository->add($species);
 
-        $id = $this->speciesRepository->findNextId();
-
-        $envelop = new Envelope(new HasBeenCreated($id));
+        $envelop = new Envelope(new HasBeenCreated(
+            $species->getId()->toRfc4122()
+        ));
 
         $this
             ->eventBus
             ->dispatch($envelop->with(new DispatchAfterCurrentBusStamp()))
         ;
 
-        return new CreateMessageResult($id);
+        return new CreateMessageResult($species->getId()->toRfc4122());
     }
 }
diff --git a/src/Stamp/LockStamp.php b/src/Stamp/LockStamp.php
index 587381d..26aee5e 100644
--- a/src/Stamp/LockStamp.php
+++ b/src/Stamp/LockStamp.php
@@ -7,7 +7,7 @@
 class LockStamp implements StampInterface
 {
     public function __construct(
-        public readonly int $lockKey
+        public readonly string $lockKey
     ) {
     }
 }