diff --git a/src/Contracts/UniqueIdentifierGenerator.php b/src/Contracts/UniqueIdentifierGenerator.php
index 5b4a17ae..ddc5af11 100644
--- a/src/Contracts/UniqueIdentifierGenerator.php
+++ b/src/Contracts/UniqueIdentifierGenerator.php
@@ -9,9 +9,9 @@ interface UniqueIdentifierGenerator
     /**
      * Generate a unique identifier.
      *
-     * @param string $domain
+     * @param string[] $domains
      * @param array $data
      * @return string
      */
-    public static function handle(string $domain, array $data = []): string;
+    public static function handle(array $domains, array $data = []): string;
 }
diff --git a/src/Tenant.php b/src/Tenant.php
index 7bc65120..26b7f007 100644
--- a/src/Tenant.php
+++ b/src/Tenant.php
@@ -6,6 +6,7 @@ namespace Stancl\Tenancy;
 
 use ArrayAccess;
 use Stancl\Tenancy\Contracts\StorageDriver;
+use Stancl\Tenancy\Contracts\UniqueIdentifierGenerator;
 
 /**
  * @internal Class is subject to breaking changes in minor and patch versions.
@@ -28,11 +29,14 @@ class Tenant implements ArrayAccess
      */
     public $domains = [];
 
+    /** @var StorageDriver */
+    protected $storage;
+
     /** @var TenantManager */
     protected $manager;
 
-    /** @var StorageDriver */
-    protected $storage;
+    /** @var UniqueIdentifierGenerator */
+    protected $idGenerator;
 
     /**
      * Does this tenant exist in the storage.
@@ -41,17 +45,16 @@ class Tenant implements ArrayAccess
      */
     protected $persisted = false;
 
-    public function __construct(TenantManager $tenantManager, StorageDriver $storage)
+    public function __construct(StorageDriver $storage, TenantManager $tenantManager, UniqueIdentifierGenerator $idGenerator)
     {
-        $this->manager = $tenantManager;
         $this->storage = $storage;
+        $this->manager = $tenantManager;
+        $this->idGenerator = $idGenerator;
     }
 
     public static function new(): self
     {
-        return app(static::class)->withData([
-            'id' => static::generateId(), // todo
-        ]);
+        return app(static::class);
     }
 
     public static function fromStorage(array $data): self
@@ -66,7 +69,6 @@ class Tenant implements ArrayAccess
         return $this;
     }
 
-    // todo move this to TenantFactory?
     public function withDomains($domains): self
     {
         $domains = (array) $domains;
@@ -83,8 +85,17 @@ class Tenant implements ArrayAccess
         return $this;
     }
 
+    public function generateId()
+    {
+        $this->id = $this->idGenerator->handle($this->domains, $this->data);
+    }
+
     public function save(): self
     {
+        if (! $this->id) {
+            $this->generateId();
+        }
+
         if ($this->persisted) {
             $this->manager->createTenant($this);
         } else {
diff --git a/src/UUIDGenerator.php b/src/UUIDGenerator.php
index 6f0fb713..80af66dc 100644
--- a/src/UUIDGenerator.php
+++ b/src/UUIDGenerator.php
@@ -4,12 +4,12 @@ declare(strict_types=1);
 
 namespace Stancl\Tenancy;
 
-use Stancl\Tenancy\Interfaces\UniqueIdentifierGenerator;
+use Stancl\Tenancy\Contracts\UniqueIdentifierGenerator;
 
 class UUIDGenerator implements UniqueIdentifierGenerator
 {
-    public static function handle(string $domain, array $data = []): string
+    public static function handle(array $domains, array $data = []): string
     {
-        return (string) \Webpatser\Uuid\Uuid::generate(1, $domain);
+        return (string) \Webpatser\Uuid\Uuid::generate(1, $domains[0] ?? '');
     }
 }