diff --git a/app/controllers/api/databases.php b/app/controllers/api/databases.php
index 4163ae258f..f2925f8360 100644
--- a/app/controllers/api/databases.php
+++ b/app/controllers/api/databases.php
@@ -1616,6 +1616,54 @@ App::post('/v1/databases/:databaseId/collections/:collectionId/attributes/relati
         $key ??= $relatedCollectionId;
         $twoWayKey ??= $collectionId;
 
+        $database = Authorization::skip(fn() => $dbForProject->getDocument('databases', $databaseId));
+
+        if ($database->isEmpty()) {
+            throw new Exception(Exception::DATABASE_NOT_FOUND);
+        }
+
+        $collection = $dbForProject->getDocument('database_' . $database->getInternalId(), $collectionId);
+        $collection = $dbForProject->getCollection('database_' . $database->getInternalId() . '_collection_' . $collection->getInternalId());
+
+        if ($collection->isEmpty()) {
+            throw new Exception(Exception::COLLECTION_NOT_FOUND);
+        }
+
+        $relatedCollectionDocument = $dbForProject->getDocument('database_' . $database->getInternalId(), $relatedCollectionId);
+        $relatedCollection = $dbForProject->getCollection('database_' . $database->getInternalId() . '_collection_' . $relatedCollectionDocument->getInternalId());
+
+        if ($relatedCollection->isEmpty()) {
+            throw new Exception(Exception::COLLECTION_NOT_FOUND);
+        }
+
+        $attributes = $collection->getAttribute('attributes', []);
+        /** @var Document[] $attributes */
+        foreach ($attributes as $attribute) {
+            if ($attribute->getAttribute('type') !== Database::VAR_RELATIONSHIP) {
+                continue;
+            }
+
+            if (\strtolower($attribute->getId()) === \strtolower($key)) {
+                throw new Exception(Exception::ATTRIBUTE_ALREADY_EXISTS);
+            }
+
+            if (
+                \strtolower($attribute->getAttribute('options')['twoWayKey']) === \strtolower($twoWayKey) &&
+                $attribute->getAttribute('options')['relatedCollection'] === $relatedCollection->getId()
+            ) {
+                // Console should provide a unique twoWayKey input!
+                throw new Exception(Exception::ATTRIBUTE_ALREADY_EXISTS, 'Attribute with the requested key already exists. Attribute keys must be unique, try again with a different key.');
+            }
+
+            if (
+                $type === Database::RELATION_MANY_TO_MANY &&
+                $attribute->getAttribute('options')['relationType'] === Database::RELATION_MANY_TO_MANY &&
+                $attribute->getAttribute('options')['relatedCollection'] === $relatedCollection->getId()
+            ) {
+                throw new Exception(Exception::ATTRIBUTE_ALREADY_EXISTS, 'Creating more than one "manyToMany" relationship on the same collection is currently not permitted.');
+            }
+        }
+
         $attribute = createAttribute(
             $databaseId,
             $collectionId,
diff --git a/tests/e2e/Services/Databases/DatabasesCustomClientTest.php b/tests/e2e/Services/Databases/DatabasesCustomClientTest.php
index 5d0a16d2e8..f91fd4ff26 100644
--- a/tests/e2e/Services/Databases/DatabasesCustomClientTest.php
+++ b/tests/e2e/Services/Databases/DatabasesCustomClientTest.php
@@ -6,6 +6,7 @@ use Tests\E2E\Client;
 use Tests\E2E\Scopes\Scope;
 use Tests\E2E\Scopes\ProjectCustom;
 use Tests\E2E\Scopes\SideClient;
+use Utopia\Database\Database;
 use Utopia\Database\Helpers\ID;
 use Utopia\Database\Helpers\Permission;
 use Utopia\Database\Helpers\Role;
@@ -316,6 +317,164 @@ class DatabasesCustomClientTest extends Scope
         $this->assertEquals('restrict', $collection1RelationAttribute['onDelete']);
     }
 
+    public function testRelationshipSameTwoWayKey(): void
+    {
+        $database = $this->client->call(Client::METHOD_POST, '/databases', [
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ], [
+            'databaseId' => ID::unique(),
+            'name' => 'Same two way key'
+        ]);
+
+        $databaseId = $database['body']['$id'];
+
+        $collection1 = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'collectionId' => ID::unique(),
+            'name' => 'c1',
+            'documentSecurity' => false,
+            'permissions' => [
+                Permission::create(Role::user($this->getUser()['$id'])),
+                Permission::read(Role::user($this->getUser()['$id'])),
+                Permission::update(Role::user($this->getUser()['$id'])),
+                Permission::delete(Role::user($this->getUser()['$id'])),
+            ]
+        ]);
+
+        $collection2 = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'collectionId' => ID::unique(),
+            'name' => 'c2',
+            'documentSecurity' => false,
+            'permissions' => [
+                Permission::create(Role::user($this->getUser()['$id'])),
+                Permission::read(Role::user($this->getUser()['$id'])),
+                Permission::update(Role::user($this->getUser()['$id'])),
+                Permission::delete(Role::user($this->getUser()['$id'])),
+            ]
+        ]);
+
+        \sleep(2);
+
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_ONE_TO_ONE,
+            'twoWay' => false,
+            'onDelete' => 'cascade',
+            'key' => 'attr1',
+            'twoWayKey' => 'same_key'
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals(202, $relation['headers']['status-code']);
+        $this->assertEquals('same_key', $relation['body']['twoWayKey']);
+
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_ONE_TO_MANY,
+            'twoWay' => false,
+            'onDelete' => 'cascade',
+            'key' => 'attr2',
+            'twoWayKey' => 'same_key'
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals(409, $relation['body']['code']);
+        $this->assertEquals('Attribute with the requested key already exists. Attribute keys must be unique, try again with a different key.', $relation['body']['message']);
+
+        // twoWayKey is null TwoWayKey is default
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_ONE_TO_MANY,
+            'twoWay' => false,
+            'onDelete' => 'cascade',
+            'key' => 'attr3',
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals(202, $relation['headers']['status-code']);
+        $this->assertArrayHasKey('twoWayKey', $relation['body']);
+
+        // twoWayKey is null,   TwoWayKey is default, second POST
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_ONE_TO_MANY,
+            'twoWay' => false,
+            'onDelete' => 'cascade',
+            'key' => 'attr4',
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals('Attribute with the requested key already exists. Attribute keys must be unique, try again with a different key.', $relation['body']['message']);
+        $this->assertEquals(409, $relation['body']['code']);
+
+        // RelationshipManyToMany
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_MANY_TO_MANY,
+            'twoWay' => true,
+            'onDelete' => 'setNull',
+            'key' => 'songs',
+            'twoWayKey' => 'playlist',
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals(202, $relation['headers']['status-code']);
+        $this->assertArrayHasKey('twoWayKey', $relation['body']);
+
+        // Second RelationshipManyToMany on Same collections
+        $relation = $this->client->call(Client::METHOD_POST, '/databases/' . $databaseId . '/collections/' . $collection1['body']['$id'] . '/attributes/relationship', array_merge([
+            'content-type' => 'application/json',
+            'x-appwrite-project' => $this->getProject()['$id'],
+            'x-appwrite-key' => $this->getProject()['apiKey']
+        ]), [
+            'relatedCollectionId' => $collection2['body']['$id'],
+            'type' => Database::RELATION_MANY_TO_MANY,
+            'twoWay' => true,
+            'onDelete' => 'setNull',
+            'key' => 'songs2',
+            'twoWayKey' => 'playlist2',
+        ]);
+
+        \sleep(2);
+
+        $this->assertEquals(409, $relation['body']['code']);
+        $this->assertEquals('Creating more than one "manyToMany" relationship on the same collection is currently not permitted.', $relation['body']['message']);
+    }
+
     public function testUpdateWithoutRelationPermission(): void
     {
         $userId = $this->getUser()['$id'];