diff --git a/src/Appwrite/Specification/Format/OpenAPI3.php b/src/Appwrite/Specification/Format/OpenAPI3.php
index b52c38503..5b4282b2d 100644
--- a/src/Appwrite/Specification/Format/OpenAPI3.php
+++ b/src/Appwrite/Specification/Format/OpenAPI3.php
@@ -20,34 +20,6 @@ class OpenAPI3 extends Format
         return 'Open API 3';
     }
 
-    /**
-     * Get Used Models
-     *
-     * Recursively get all used models
-     *
-     * @param object $model
-     * @param array $models
-     *
-     * @return void
-     */
-    protected function getUsedModels($model, array &$usedModels)
-    {
-        if (is_string($model) && !in_array($model, ['string', 'integer', 'boolean', 'json', 'float', 'double'])) {
-            $usedModels[] = $model;
-            return;
-        }
-        if (!is_object($model)) return;
-        foreach ($model->getRules() as $rule) {
-            if(\is_array($rule['type'])) {
-                foreach ($rule['type'] as $type) {
-                    $this->getUsedModels($type, $usedModels);
-                }
-            } else {
-                $this->getUsedModels($rule['type'], $usedModels);
-            }
-        }
-    }
-
     /**
      * Parse
      *
@@ -422,7 +394,11 @@ class OpenAPI3 extends Format
             $output['paths'][$url][\strtolower($route->getMethod())] = $temp;
         }
         foreach ($this->models as $model) {
-            $this->getUsedModels($model, $usedModels);
+            foreach ($model->getRules() as $rule) {
+                if (!in_array($rule['type'], ['string', 'integer', 'boolean', 'json', 'float'])) {
+                    $usedModels[] = $rule['type'];
+                }
+            }
         }
         foreach ($this->models as $model) {
             if (!in_array($model->getType(), $usedModels) && $model->getType() !== 'error') {
@@ -526,7 +502,6 @@ class OpenAPI3 extends Format
                     $output['components']['schemas'][$model->getType()]['properties'][$name] = [
                         'type' => $type,
                         'description' => $rule['description'] ?? '',
-                        //'default' => $rule['default'] ?? null,
                         'x-example' => $rule['example'] ?? null,
                     ];
 
@@ -538,6 +513,9 @@ class OpenAPI3 extends Format
                         $output['components']['schemas'][$model->getType()]['properties'][$name]['items'] = $items;
                     }
                 }
+                if (!in_array($name, $required)) {
+                    $output['components']['schemas'][$model->getType()]['properties'][$name]['nullable'] = true;
+                }
             }
         }
 
diff --git a/src/Appwrite/Specification/Format/Swagger2.php b/src/Appwrite/Specification/Format/Swagger2.php
index ab45ae401..595f5db84 100644
--- a/src/Appwrite/Specification/Format/Swagger2.php
+++ b/src/Appwrite/Specification/Format/Swagger2.php
@@ -20,34 +20,6 @@ class Swagger2 extends Format
         return 'Swagger 2';
     }
 
-    /**
-     * Get Used Models
-     *
-     * Recursively get all used models
-     * 
-     * @param object $model
-     * @param array $models
-     *
-     * @return void
-     */
-    protected function getUsedModels($model, array &$usedModels)
-    {
-        if (is_string($model) && !in_array($model, ['string', 'integer', 'boolean', 'json', 'float', 'double'])) {
-            $usedModels[] = $model;
-            return;
-        }
-        if (!is_object($model)) return;
-        foreach ($model->getRules() as $rule) {
-            if(\is_array($rule['type'])) {
-                foreach ($rule['type'] as $type) {
-                    $this->getUsedModels($type, $usedModels);
-                }
-            } else {
-                $this->getUsedModels($rule['type'], $usedModels);
-            }
-        }
-    }
-
     /**
      * Parse
      *
@@ -308,7 +280,7 @@ class Swagger2 extends Format
                     case 'Utopia\Validator\Mock':
                     case 'Utopia\Validator\Assoc':
                         $node['type'] = 'object';
-                        $param['default'] = (empty($param['default'])) ? new \stdClass() : $param['default'];
+                        $node['default'] = (empty($param['default'])) ? new \stdClass() : $param['default'];
                         $node['x-example'] = '{}';
                         //$node['format'] = 'json';
                         break;
@@ -379,14 +351,14 @@ class Swagger2 extends Format
                     $temp['parameters'][] = $node;
                 } else { // Param is in payload
 
-                    if(\in_array('multipart/form-data', $consumes)) {
+                    if (\in_array('multipart/form-data', $consumes)) {
                         $node['in'] = 'formData';
                         $temp['parameters'][] = $node;
 
                         continue;
                     }
 
-                    if(!$param['optional']) {
+                    if (!$param['optional']) {
                         $bodyRequired[] = $name;
                     }
 
@@ -417,8 +389,16 @@ class Swagger2 extends Format
 
             $output['paths'][$url][\strtolower($route->getMethod())] = $temp;
         }
+
         foreach ($this->models as $model) {
-            $this->getUsedModels($model, $usedModels);
+            foreach ($model->getRules() as $rule) {
+                if (
+                    in_array($model->getType(), $usedModels)
+                    && !in_array($rule['type'], ['string', 'integer', 'boolean', 'json', 'float'])
+                ) {
+                    $usedModels[] = $rule['type'];
+                }
+            }
         }
 
         foreach ($this->models as $model) {
@@ -536,6 +516,9 @@ class Swagger2 extends Format
                         $output['definitions'][$model->getType()]['properties'][$name]['items'] = $items;
                     }
                 }
+                if (!in_array($name, $required)) {
+                    $output['definitions'][$model->getType()]['properties'][$name]['nullable'] = true;
+                }
             }
         }
 
diff --git a/src/Appwrite/Utopia/Response/Model.php b/src/Appwrite/Utopia/Response/Model.php
index affe21767..9a98e55ea 100644
--- a/src/Appwrite/Utopia/Response/Model.php
+++ b/src/Appwrite/Utopia/Response/Model.php
@@ -92,7 +92,7 @@ abstract class Model
         $list = [];
 
         foreach ($this->rules as $key => $rule) {
-            if (isset($rule['require']) || $rule['require']) {
+            if ($rule['require'] ?? false) {
                 $list[] = $key;
             }
         }