The Serializable interface

(PHP 5 >= 5.1.0, PHP 7, PHP 8)


Interface for customized serializing.

Classes that implement this interface no longer support __sleep() and __wakeup(). The method serialize is called whenever an instance needs to be serialized. This does not invoke __destruct() or have any other side effect unless programmed inside the method. When the data is unserialized the class is known and the appropriate unserialize() method is called as a constructor instead of calling __construct(). If you need to execute the standard constructor you may do so in the method.


As of PHP 8.1.0, a class which implements Serializable without also implementing __serialize() and __unserialize() will generate a deprecation warning.

Interface synopsis

interface Serializable {
/* Methods */
public serialize(): ?string
public unserialize(string $data): void

Example #1 Basic usage

class obj implements Serializable {
    public function 
__construct() {
$this->data "My private data";
    public function 
serialize() {
    public function 
unserialize($data) {
$this->data unserialize($data);
    public function 
getData() {

$obj = new obj;
$ser serialize($obj);


$newobj unserialize($ser);


The above example will output something similar to:

string(38) "C:3:"obj":23:{s:15:"My private data";}"
string(15) "My private data"

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