The URLSearchParams class implements utility methods to work with the query string of a URL as defined by the WHATWG group.

This means that you can use this class anytime you need a compliant URLSearchParams object. To improve its usage the class also exposes the package common API and implements the following PHP interfaces:

  • Countable,
  • IteratorAggregate,
  • Stringable,
  • and JsonSerializable

To get the full information on the class behaviour and feature you can go to the MDN page. But since we are in a PHP context the class differs in the following aspects:

WHATWG group Specification PHP implementation
URLSearchParams::size property URLSearchParams::size()method
URLSearchParams::forEach() URLSearchParams::each()

As per the specification the class is mutable.

As per the specification encoding is done following the application/x-www-form-urlencoded rules



To instantiate a new instance you can use the default constructor which follow the specification or one of the more specialized named constructors to avoid subtle bugs described below:

  • The URLSearchParams::new instantiate from a query; the ? delimiter if present will be ignored.
  • The URLSearchParams::fromUri instantiate from a URI.
  • The URLSearchParams::fromPairs instantiate from a collection of pairs.
  • The URLSearchParams::fromAssociative instantiate from an associative array or any object with public properties or generic key/value iterator (nested value are not supported).
  • The URLSearchParams::fromVariable instantiate from the result of parse_str or the input of http_build_query.
$parameters = [
    'filter' => [
        'dateRange' => [
            'start' => '2023-01-01',
            'end' => '2023-08-31',

$params = URLSearchParams::fromVariable($parameters);
$params->get('filter[dateRange][start]'); //returns '2023-01-01
echo $params; 
//display "filter%5BdateRange%5D%5Bstart%5D=2023-01-01&filter%5BdateRange%5D%5Bend%5D=2023-08-31"

$interval = new DateInterval('P3MT12M5S');
echo URLSearchParams::fromAssociative($interval)->toString();
//display "y=0&m=3&d=0&h=0&i=12&s=5&f=0&invert=0&days=false&from_string=false"

To adhere to the specification, if a string starts with the character ?; URLSearchParams::new will ignore it before parsing the string.

URLSearchParams::fromVariable replaced the deprecated URLSearchParams::fromParameters named constructor which was not inconsistent against http_build_query algorithm.

use League\Uri\Components\URLSearchParams;

echo URLSearchParams::new('?a=b')->toString();
echo URLSearchParams::new('a=b')->toString(); 
echo (new URLSearchParams('?a=b'))->toString();
//all the above code will display 'a=b'
//to preserve the question mark you need to encode it.
[...URLSearchParams::new('%3Fa=b')]; // returns [['?a', 'b']]
[...(new URLSearchParams('%3Fa=b'))];  // returns [['?a', 'b']]

Accessing and manipulating the data

While the class implements all the methods define in the RFC, the following methods are added to ease usage.

  • URLSearchParams::isEmpty
  • URLSearchParams::isNotEmpty
  • URLSearchParams::uniqueKeyCount new in version 7.5.0
use League\Uri\Components\URLSearchParams;

$params = new URLSearchParams('foo=bar&bar=baz+bar&foo=baz');
$params->isNotEmpty(); //returns true
$params->isEmpty(); //returns false
$params->get('foo'); //returns 'bar'
$params->getAll('foo'); //returns ['bar', 'baz']
$params->has('foo'); //returns true
$params->has('foo', 'bar'); //returns true
$params->has('foo', 'toto'); //returns false (the second parameter is the value of the pair)
count($params); //returns 3
$params->size();  //returns 3
$params->uniqueKeyCount(); //returns 2
count($params); //returns 1 (because all the pairs which contains foo have been removed)
$params->set('aha', true);
$params->append('aha', null);
$params->get('foo'); //returns null
$params->get('bar'); //returns "baz bar"
echo $params->toString(); //returns "aha=true&aha=null&bar=baz+bar"