diff --git a/src/Entities/Account.php b/src/Entities/Account.php
index 56ce327..f6ff245 100644
--- a/src/Entities/Account.php
+++ b/src/Entities/Account.php
@@ -19,11 +19,14 @@ namespace D3\KlicktippPhpClient\Entities;
 
 use D3\KlicktippPhpClient\Exceptions\CommunicationException;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Account as AccountEndpoint;
 use Doctrine\Common\Collections\ArrayCollection;
 
 class Account extends Entity
 {
+    use EndpointTrait;
+
     private ?AccountEndpoint $endpoint;
 
     public function __construct(array $elements = [], ?AccountEndpoint $endpoint = null)
@@ -193,9 +196,10 @@ class Account extends Entity
     /**
      * @return null|bool
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     public function persist(): ?bool
     {
-        return $this->endpoint?->update();
+        return $this->getEndpoint()->update();
     }
 }
diff --git a/src/Entities/EndpointTrait.php b/src/Entities/EndpointTrait.php
new file mode 100644
index 0000000..8db7f80
--- /dev/null
+++ b/src/Entities/EndpointTrait.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * Copyright (c) D3 Data Development (Inh. Thomas Dartsch)
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <info@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\KlicktippPhpClient\Entities;
+
+use Assert\Assert;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
+use D3\KlicktippPhpClient\Resources\Model;
+
+trait EndpointTrait
+{
+    private function getEndpoint(): Model
+    {
+        Assert::lazy()
+              ->setExceptionClass(MissingEndpointException::class)
+              ->that($this->endpoint)
+              ->isInstanceOf(Model::class)
+              ->verifyNow();
+
+        return $this->endpoint;
+    }
+}
diff --git a/src/Entities/Field.php b/src/Entities/Field.php
index 9608ab7..3d8bf11 100644
--- a/src/Entities/Field.php
+++ b/src/Entities/Field.php
@@ -18,10 +18,13 @@ declare(strict_types=1);
 namespace D3\KlicktippPhpClient\Entities;
 
 use D3\KlicktippPhpClient\Exceptions\CommunicationException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Field as FieldEndpoint;
 
 class Field extends Entity
 {
+    use EndpointTrait;
+
     private ?FieldEndpoint $endpoint;
 
     public function __construct(array $elements = [], ?FieldEndpoint $endpoint = null)
@@ -50,11 +53,12 @@ class Field extends Entity
     /**
      * @return null|bool
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     public function persist(): ?bool
     {
         return !is_null($this->getId()) ?
-            $this->endpoint?->update(
+            $this->getEndpoint()->update(
                 $this->getId(),
                 $this->getName() ?? ''
             ) :
diff --git a/src/Entities/Subscriber.php b/src/Entities/Subscriber.php
index 49f361a..badc0df 100644
--- a/src/Entities/Subscriber.php
+++ b/src/Entities/Subscriber.php
@@ -18,12 +18,15 @@ declare(strict_types=1);
 namespace D3\KlicktippPhpClient\Entities;
 
 use D3\KlicktippPhpClient\Exceptions\CommunicationException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Subscriber as SubscriberEndpoint;
 use DateTime;
 use Doctrine\Common\Collections\ArrayCollection;
 
 class Subscriber extends Entity
 {
+    use EndpointTrait;
+
     public const STATUS_SUBSCRIBED = 'subscribed';
     public const BOUNCE_NOTBOUNCED = 'Not Bounced';
 
@@ -314,11 +317,12 @@ class Subscriber extends Entity
     /**
      * @return null|bool
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     public function persist(): ?bool
     {
         if (!is_null($this->getId())) {
-            $return = $this->endpoint?->update(
+            $return = $this->getEndpoint()->update(
                 $this->getId(),
                 $this->getFields()->toArray(),
                 $this->getEmailAddress() ?? '',
@@ -335,14 +339,11 @@ class Subscriber extends Entity
 
     /**
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     protected function persistTags(): void
     {
-        if (!$this->endpoint instanceof SubscriberEndpoint) {
-            return;
-        }
-
-        $currentTags = $this->endpoint->getEntity($this->getId() ?? '')->getTags();
+        $currentTags = $this->getEndpoint()->getEntity($this->getId() ?? '')->getTags();
 
         $removeTags = array_diff(
             $currentTags?->toArray() ?? [],
@@ -352,7 +353,7 @@ class Subscriber extends Entity
         if (count($removeTags)) {
             foreach ($removeTags as $removeTag) {
                 if (!is_null($this->getEmailAddress())) {
-                    $this->endpoint->untag($this->getEmailAddress(), $removeTag);
+                    $this->getEndpoint()->untag($this->getEmailAddress(), $removeTag);
                 }
             }
         }
@@ -363,7 +364,7 @@ class Subscriber extends Entity
         );
         if (count($addTags)) {
             if (!is_null($this->getEmailAddress())) {
-                $this->endpoint->tag($this->getEmailAddress(), $addTags);
+                $this->getEndpoint()->tag($this->getEmailAddress(), $addTags);
             }
         }
     }
@@ -384,7 +385,7 @@ class Subscriber extends Entity
         ?string $smsNumber = null
     ): void {
         if (!$this->isSubscribed()) {
-            $this->endpoint->subscribe(
+            $this->getEndpoint()->subscribe(
                 $this->getEmailAddress(),
                 $listId,
                 $tagId,
diff --git a/src/Entities/Subscription.php b/src/Entities/Subscription.php
index 9f1e3f1..17e1586 100644
--- a/src/Entities/Subscription.php
+++ b/src/Entities/Subscription.php
@@ -18,10 +18,13 @@ declare(strict_types=1);
 namespace D3\KlicktippPhpClient\Entities;
 
 use D3\KlicktippPhpClient\Exceptions\CommunicationException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\SubscriptionProcess;
 
 class Subscription extends Entity
 {
+    use EndpointTrait;
+
     private ?SubscriptionProcess $endpoint;
 
     public function __construct(array $elements = [], ?SubscriptionProcess $endpoint = null)
@@ -78,11 +81,12 @@ class Subscription extends Entity
     /**
      * @return null|bool
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     public function persist(): ?bool
     {
         return !is_null($this->getListId()) ?
-            $this->endpoint?->update(
+            $this->getEndpoint()->update(
                 $this->getListId(),
                 $this->getName() ?? ''
             ) :
diff --git a/src/Entities/Tag.php b/src/Entities/Tag.php
index f0ee888..6c5ab32 100644
--- a/src/Entities/Tag.php
+++ b/src/Entities/Tag.php
@@ -18,10 +18,13 @@ declare(strict_types=1);
 namespace D3\KlicktippPhpClient\Entities;
 
 use D3\KlicktippPhpClient\Exceptions\CommunicationException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Tag as TagEndpoint;
 
 class Tag extends Entity
 {
+    use EndpointTrait;
+
     private ?TagEndpoint $endpoint;
 
     public function __construct(array $elements = [], ?TagEndpoint $endpoint = null)
@@ -62,11 +65,12 @@ class Tag extends Entity
     /**
      * @return null|bool
      * @throws CommunicationException
+     * @throws MissingEndpointException
      */
     public function persist(): ?bool
     {
         return !is_null($this->getId()) ?
-            $this->endpoint?->update(
+            $this->getEndpoint()->update(
                 $this->getId(),
                 $this->getName() ?? '',
                 $this->getText() ?? ''
diff --git a/src/Exceptions/MissingEndpointException.php b/src/Exceptions/MissingEndpointException.php
new file mode 100644
index 0000000..53b446b
--- /dev/null
+++ b/src/Exceptions/MissingEndpointException.php
@@ -0,0 +1,29 @@
+<?php
+
+/**
+ * Copyright (c) D3 Data Development (Inh. Thomas Dartsch)
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <info@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\KlicktippPhpClient\Exceptions;
+
+use Assert\LazyAssertionException;
+
+class MissingEndpointException extends LazyAssertionException implements KlicktippExceptionInterface
+{
+    public function __construct($message, array $errors)
+    {
+        unset($message);
+        parent::__construct('required endpoint for this action missing', $errors);
+    }
+}
diff --git a/tests/unit/Entities/AccountTest.php b/tests/unit/Entities/AccountTest.php
index f57cea0..026317c 100644
--- a/tests/unit/Entities/AccountTest.php
+++ b/tests/unit/Entities/AccountTest.php
@@ -19,6 +19,7 @@ namespace D3\KlicktippPhpClient\tests\unit\Entities;
 
 use D3\KlicktippPhpClient\Entities\Account;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Account as AccountEndpoint;
 use D3\KlicktippPhpClient\tests\TestCase;
 use Doctrine\Common\Collections\ArrayCollection;
@@ -526,6 +527,10 @@ class AccountTest extends TestCase
 
         $sut = new Account([AccountEndpoint::UID => 'foo'], $endpointSet ? $endpointMock : null);
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->assertSame(
             $expectedReturn,
             $this->callMethod(
diff --git a/tests/unit/Entities/FieldTest.php b/tests/unit/Entities/FieldTest.php
index 6d44a96..da35395 100644
--- a/tests/unit/Entities/FieldTest.php
+++ b/tests/unit/Entities/FieldTest.php
@@ -19,6 +19,7 @@ namespace D3\KlicktippPhpClient\tests\unit\Entities;
 
 use D3\KlicktippPhpClient\Entities\Field;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Field as FieldEndpoint;
 use D3\KlicktippPhpClient\tests\TestCase;
 use Generator;
@@ -184,6 +185,10 @@ class FieldTest extends TestCase
             $endpointSet ? $endpointMock : null
         );
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->assertSame(
             $expectedReturn,
             $this->callMethod(
diff --git a/tests/unit/Entities/SubscriberTest.php b/tests/unit/Entities/SubscriberTest.php
index d7c063c..f0773b7 100644
--- a/tests/unit/Entities/SubscriberTest.php
+++ b/tests/unit/Entities/SubscriberTest.php
@@ -19,6 +19,7 @@ namespace D3\KlicktippPhpClient\tests\unit\Entities;
 
 use D3\KlicktippPhpClient\Entities\Subscriber;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Subscriber as SubscriberEndpoint;
 use D3\KlicktippPhpClient\tests\TestCase;
 use DateTime;
@@ -844,6 +845,10 @@ class SubscriberTest extends TestCase
             ->getMock();
         $sut->expects($persistTagsInvocation)->method('persistTags');
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->assertSame(
             $expectedReturn,
             $this->callMethod(
@@ -856,7 +861,7 @@ class SubscriberTest extends TestCase
     public static function persistDataProvider(): Generator
     {
         yield 'has endpoint'    => [true, 'fixture', self::once(), self::once(), true];
-        yield 'has no endpoint'    => [false, 'fixture', self::never(), self::once(), null];
+        yield 'has no endpoint'    => [false, 'fixture', self::never(), self::never(), null];
         yield 'has endpoint, no id' => [true, null, self::never(), self::never(), null];
     }
 
@@ -895,6 +900,10 @@ class SubscriberTest extends TestCase
             $sut->set('tags', $newTagList);
         }
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->callMethod(
             $sut,
             'persistTags'
@@ -983,14 +992,14 @@ class SubscriberTest extends TestCase
      * @test
      * @throws ReflectionException
      * @covers \D3\KlicktippPhpClient\Entities\Subscriber::resubscribe
+     * @covers \D3\KlicktippPhpClient\Entities\Subscriber::getEndpoint
      * @dataProvider  resubscribeDataProvider
      */
     public function testReSubscribe(
         bool $endpointSet,
         InvokedCount $subscribeExpections,
         bool $isSubscribed
-    ): void
-    {
+    ): void {
         $endpointMock = $this->getMockBuilder(SubscriberEndpoint::class)
             ->disableOriginalConstructor()
             ->onlyMethods(['subscribe'])
@@ -1004,6 +1013,10 @@ class SubscriberTest extends TestCase
         $sut->method('isSubscribed')->willReturn($isSubscribed);
         $sut->method('getEmailAddress')->willReturn('mail@mydomain.tld');
 
+        if (!$endpointSet && !$isSubscribed) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->callMethod(
             $sut,
             'resubscribe',
diff --git a/tests/unit/Entities/SubscriptionTest.php b/tests/unit/Entities/SubscriptionTest.php
index f27a489..aa8cf4e 100644
--- a/tests/unit/Entities/SubscriptionTest.php
+++ b/tests/unit/Entities/SubscriptionTest.php
@@ -19,6 +19,7 @@ namespace D3\KlicktippPhpClient\tests\unit\Entities;
 
 use D3\KlicktippPhpClient\Entities\Subscription;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\SubscriptionProcess as SubscriptionEndpoint;
 use D3\KlicktippPhpClient\tests\TestCase;
 use Generator;
@@ -223,6 +224,10 @@ class SubscriptionTest extends TestCase
             $endpointSet ? $endpointMock : null
         );
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->assertSame(
             $expectedReturn,
             $this->callMethod(
diff --git a/tests/unit/Entities/TagTest.php b/tests/unit/Entities/TagTest.php
index 828b18d..a8fa4a5 100644
--- a/tests/unit/Entities/TagTest.php
+++ b/tests/unit/Entities/TagTest.php
@@ -19,6 +19,7 @@ namespace D3\KlicktippPhpClient\tests\unit\Entities;
 
 use D3\KlicktippPhpClient\Entities\Tag;
 use D3\KlicktippPhpClient\Exceptions\InvalidCredentialTypeException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
 use D3\KlicktippPhpClient\Resources\Tag as TagEndpoint;
 use D3\KlicktippPhpClient\tests\TestCase;
 use Generator;
@@ -198,6 +199,10 @@ class TagTest extends TestCase
             $endpointSet ? $endpointMock : null
         );
 
+        if (!$endpointSet) {
+            $this->expectException(MissingEndpointException::class);
+        }
+
         $this->assertSame(
             $expectedReturn,
             $this->callMethod(
diff --git a/tests/unit/Exceptions/MissingEndpointExceptionTest.php b/tests/unit/Exceptions/MissingEndpointExceptionTest.php
new file mode 100644
index 0000000..2d6c009
--- /dev/null
+++ b/tests/unit/Exceptions/MissingEndpointExceptionTest.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+ * Copyright (c) D3 Data Development (Inh. Thomas Dartsch)
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <info@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\KlicktippPhpClient\tests\unit\Exceptions;
+
+use D3\KlicktippPhpClient\Exceptions\CommunicationException;
+use D3\KlicktippPhpClient\Exceptions\MissingEndpointException;
+use D3\KlicktippPhpClient\tests\TestCase;
+use ReflectionException;
+
+/**
+ * @covers \D3\KlicktippPhpClient\Exceptions\MissingEndpointException
+ */
+class MissingEndpointExceptionTest extends TestCase
+{
+    /**
+     * @test
+     * @return void
+     * @throws ReflectionException
+     * @covers \D3\KlicktippPhpClient\Exceptions\MissingEndpointException::__construct
+     */
+    public function testConstructor(): void
+    {
+        /** @var MissingEndpointException $sutMock */
+        $sutMock = $this->getMockBuilder(MissingEndpointException::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->callMethod(
+            $sutMock,
+            '__construct',
+            ['myMessage', []]
+        );
+
+        $this->assertMatchesRegularExpression(
+            '/.*?endpoint.*?missing.*/i',
+            $sutMock->getMessage()
+        );
+    }
+}