diff --git a/modules/openapi-generator/src/main/resources/php/model_generic.mustache b/modules/openapi-generator/src/main/resources/php/model_generic.mustache
index ec2140c2a9d..8099e7dc18f 100644
--- a/modules/openapi-generator/src/main/resources/php/model_generic.mustache
+++ b/modules/openapi-generator/src/main/resources/php/model_generic.mustache
@@ -1,4 +1,4 @@
-class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^parentSchema}}implements ModelInterface, ArrayAccess{{/parentSchema}}
+class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^parentSchema}}implements ModelInterface, ArrayAccess, \JsonSerializable{{/parentSchema}}
 {
     public const DISCRIMINATOR = {{#discriminator}}'{{discriminatorName}}'{{/discriminator}}{{^discriminator}}null{{/discriminator}};
 
@@ -400,6 +400,18 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^pa
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
index 81a3499d8d7..daf4cd03553 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/AdditionalPropertiesClass.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class AdditionalPropertiesClass implements ModelInterface, ArrayAccess
+class AdditionalPropertiesClass implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class AdditionalPropertiesClass implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
index a271cc089bf..9066533e9b7 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Animal.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Animal implements ModelInterface, ArrayAccess
+class Animal implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = 'class_name';
 
@@ -321,6 +321,18 @@ class Animal implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
index e79cbda775c..a3b83b0cfa4 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ApiResponse.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ApiResponse implements ModelInterface, ArrayAccess
+class ApiResponse implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -345,6 +345,18 @@ class ApiResponse implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
index 1678eae2ede..d0fda8d6114 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfArrayOfNumberOnly.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ArrayOfArrayOfNumberOnly implements ModelInterface, ArrayAccess
+class ArrayOfArrayOfNumberOnly implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class ArrayOfArrayOfNumberOnly implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
index be734d3b197..bab8cb3bf6e 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayOfNumberOnly.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ArrayOfNumberOnly implements ModelInterface, ArrayAccess
+class ArrayOfNumberOnly implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class ArrayOfNumberOnly implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
index 7a75b3a8890..dca12a3300b 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ArrayTest.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ArrayTest implements ModelInterface, ArrayAccess
+class ArrayTest implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -345,6 +345,18 @@ class ArrayTest implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
index 87facb63e0c..ae16be4ad11 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Capitalization.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Capitalization implements ModelInterface, ArrayAccess
+class Capitalization implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -435,6 +435,18 @@ class Capitalization implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
index dec9256e001..d4b42305f5b 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Cat.php
@@ -279,6 +279,18 @@ class Cat extends Animal
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/CatAllOf.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/CatAllOf.php
index cb687fa898e..0762d914d84 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/CatAllOf.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/CatAllOf.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class CatAllOf implements ModelInterface, ArrayAccess
+class CatAllOf implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class CatAllOf implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
index c3c3602e9f9..e6fdac7f010 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Category.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Category implements ModelInterface, ArrayAccess
+class Category implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -318,6 +318,18 @@ class Category implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
index 041b6337be9..fb175d42647 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ClassModel.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ClassModel implements ModelInterface, ArrayAccess
+class ClassModel implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -286,6 +286,18 @@ class ClassModel implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
index 5be1902d0a2..a14f1c0b221 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Client.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Client implements ModelInterface, ArrayAccess
+class Client implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class Client implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
index d4eb2811544..eba46f532f3 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Dog.php
@@ -279,6 +279,18 @@ class Dog extends Animal
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DogAllOf.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DogAllOf.php
index 9696b379476..acc78baf26f 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DogAllOf.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/DogAllOf.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class DogAllOf implements ModelInterface, ArrayAccess
+class DogAllOf implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class DogAllOf implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
index 1b1436fe18f..2275c05aac1 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumArrays.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class EnumArrays implements ModelInterface, ArrayAccess
+class EnumArrays implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -371,6 +371,18 @@ class EnumArrays implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
index 397dddb1c20..118a0a2ae09 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/EnumTest.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class EnumTest implements ModelInterface, ArrayAccess
+class EnumTest implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -630,6 +630,18 @@ class EnumTest implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
index 071669c48d4..aef77faed22 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/File.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class File implements ModelInterface, ArrayAccess
+class File implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -286,6 +286,18 @@ class File implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
index be014cca129..e68c14dcc19 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FileSchemaTestClass.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class FileSchemaTestClass implements ModelInterface, ArrayAccess
+class FileSchemaTestClass implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class FileSchemaTestClass implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
index 152b602f451..e1321ebb448 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Foo.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Foo implements ModelInterface, ArrayAccess
+class Foo implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class Foo implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
index 817764f8c37..124db285c26 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/FormatTest.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class FormatTest implements ModelInterface, ArrayAccess
+class FormatTest implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -839,6 +839,18 @@ class FormatTest implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
index 78a8753aca7..65115a0d50d 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HasOnlyReadOnly.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class HasOnlyReadOnly implements ModelInterface, ArrayAccess
+class HasOnlyReadOnly implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class HasOnlyReadOnly implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HealthCheckResult.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HealthCheckResult.php
index 73f41bd67eb..8c4ad1a6376 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HealthCheckResult.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/HealthCheckResult.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class HealthCheckResult implements ModelInterface, ArrayAccess
+class HealthCheckResult implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -286,6 +286,18 @@ class HealthCheckResult implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject.php
index 4f621cd478a..7276352b917 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject implements ModelInterface, ArrayAccess
+class InlineObject implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class InlineObject implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject1.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject1.php
index 5a8e35b8463..6f675c2c744 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject1.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject1.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject1 implements ModelInterface, ArrayAccess
+class InlineObject1 implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class InlineObject1 implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject2.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject2.php
index 5bc7a4051fb..e932c0923e5 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject2.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject2.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject2 implements ModelInterface, ArrayAccess
+class InlineObject2 implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -373,6 +373,18 @@ class InlineObject2 implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject3.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject3.php
index c578cb156d2..ba3ddd211b4 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject3.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject3.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject3 implements ModelInterface, ArrayAccess
+class InlineObject3 implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -793,6 +793,18 @@ class InlineObject3 implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject4.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject4.php
index 5fd4bc02241..4ec235df1f3 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject4.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject4.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject4 implements ModelInterface, ArrayAccess
+class InlineObject4 implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -321,6 +321,18 @@ class InlineObject4 implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject5.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject5.php
index af2410338d5..eef18f95db2 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject5.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineObject5.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineObject5 implements ModelInterface, ArrayAccess
+class InlineObject5 implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -318,6 +318,18 @@ class InlineObject5 implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineResponseDefault.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineResponseDefault.php
index d59fd178654..8ee7005ed47 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineResponseDefault.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/InlineResponseDefault.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class InlineResponseDefault implements ModelInterface, ArrayAccess
+class InlineResponseDefault implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class InlineResponseDefault implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
index 055a190f94a..4f90f8bd3c9 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MapTest.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class MapTest implements ModelInterface, ArrayAccess
+class MapTest implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -399,6 +399,18 @@ class MapTest implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
index 92b5bd77972..8da96c23d7b 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/MixedPropertiesAndAdditionalPropertiesClass.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class MixedPropertiesAndAdditionalPropertiesClass implements ModelInterface, ArrayAccess
+class MixedPropertiesAndAdditionalPropertiesClass implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -345,6 +345,18 @@ class MixedPropertiesAndAdditionalPropertiesClass implements ModelInterface, Arr
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
index 820f723b075..d3448a08a6c 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Model200Response.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Model200Response implements ModelInterface, ArrayAccess
+class Model200Response implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -316,6 +316,18 @@ class Model200Response implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
index 68e72f7babc..597e5637ac3 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelList.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ModelList implements ModelInterface, ArrayAccess
+class ModelList implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class ModelList implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
index b36cab5bef2..bfcc6592f09 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ModelReturn.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ModelReturn implements ModelInterface, ArrayAccess
+class ModelReturn implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -286,6 +286,18 @@ class ModelReturn implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
index 373384beb13..2817922a7f8 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Name.php
@@ -44,7 +44,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Name implements ModelInterface, ArrayAccess
+class Name implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -379,6 +379,18 @@ class Name implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
index e3882176118..2ae73e01826 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NullableClass.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class NullableClass implements ModelInterface, ArrayAccess
+class NullableClass implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -615,6 +615,18 @@ class NullableClass implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
index e1711295beb..7c0d0a412ce 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/NumberOnly.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class NumberOnly implements ModelInterface, ArrayAccess
+class NumberOnly implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class NumberOnly implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
index dcecafd9a80..6fce620c942 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Order.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Order implements ModelInterface, ArrayAccess
+class Order implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -469,6 +469,18 @@ class Order implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
index a66e335b1a2..45680560515 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/OuterComposite.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class OuterComposite implements ModelInterface, ArrayAccess
+class OuterComposite implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -345,6 +345,18 @@ class OuterComposite implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
index ff197d2c3ff..38f84c84ec5 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Pet.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Pet implements ModelInterface, ArrayAccess
+class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -475,6 +475,18 @@ class Pet implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
index fe323668361..3c08bcd2990 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/ReadOnlyFirst.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class ReadOnlyFirst implements ModelInterface, ArrayAccess
+class ReadOnlyFirst implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class ReadOnlyFirst implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
index 967231c35ff..aca6db8790e 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/SpecialModelName.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class SpecialModelName implements ModelInterface, ArrayAccess
+class SpecialModelName implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -285,6 +285,18 @@ class SpecialModelName implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
index f4f85825e58..60f6c738ab6 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/Tag.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class Tag implements ModelInterface, ArrayAccess
+class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -315,6 +315,18 @@ class Tag implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
index f2436c70ad4..555268a5814 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Model/User.php
@@ -43,7 +43,7 @@ use \OpenAPI\Client\ObjectSerializer;
  * @template TKey int|null
  * @template TValue mixed|null  
  */
-class User implements ModelInterface, ArrayAccess
+class User implements ModelInterface, ArrayAccess, \JsonSerializable
 {
     public const DISCRIMINATOR = null;
 
@@ -495,6 +495,18 @@ class User implements ModelInterface, ArrayAccess
         unset($this->container[$offset]);
     }
 
+    /**
+     * Serializes the object to a value that can be serialized natively by json_encode().
+     * @link https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     *
+     * @return mixed Returns data which can be serialized by json_encode(), which is a value
+     * of any type other than a resource.
+     */
+    public function jsonSerialize()
+    {
+       return ObjectSerializer::sanitizeForSerialization($this);
+    }
+
     /**
      * Gets the string presentation of the object
      *