Content Negotiation tools for PHP provided as a standalone library.

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3.1.0 2022-01-30 20:08 UTC


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Negotiation is a standalone library without any dependencies that allows you to implement content negotiation in your application, whatever framework you use. This library is based on RFC 7231. Negotiation is easy to use, and extensively unit tested!

Important: You are browsing the documentation of Negotiation 3.x+.

Documentation for version 1.x is available here: Negotiation 1.x documentation.

Documentation for version 2.x is available here: Negotiation 2.x documentation.


The recommended way to install Negotiation is through Composer:

$ composer require willdurand/negotiation

Usage Examples

Media Type Negotiation

$negotiator = new \Negotiation\Negotiator();

$acceptHeader = 'text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8';
$priorities   = array('text/html; charset=UTF-8', 'application/json', 'application/xml;q=0.5');

$mediaType = $negotiator->getBest($acceptHeader, $priorities);

$value = $mediaType->getValue();
// $value == 'text/html; charset=UTF-8'

The Negotiator returns an instance of Accept, or null if negotiating the best media type has failed.

Language Negotiation


$negotiator = new \Negotiation\LanguageNegotiator();

$acceptLanguageHeader = 'en; q=0.1, fr; q=0.4, fu; q=0.9, de; q=0.2';
$priorities          = array('de', 'fu', 'en');

$bestLanguage = $negotiator->getBest($acceptLanguageHeader, $priorities);

$type = $bestLanguage->getType();
// $type == 'fu';

$quality = $bestLanguage->getQuality();
// $quality == 0.9

The LanguageNegotiator returns an instance of AcceptLanguage.

Encoding Negotiation


$negotiator = new \Negotiation\EncodingNegotiator();
$encoding   = $negotiator->getBest($acceptHeader, $priorities);

The EncodingNegotiator returns an instance of AcceptEncoding.

Charset Negotiation


$negotiator = new \Negotiation\CharsetNegotiator();

$acceptCharsetHeader = 'ISO-8859-1, UTF-8; q=0.9';
$priorities          = array('iso-8859-1;q=0.3', 'utf-8;q=0.9', 'utf-16;q=1.0');

$bestCharset = $negotiator->getBest($acceptCharsetHeader, $priorities);

$type = $bestCharset->getType();
// $type == 'utf-8';

$quality = $bestCharset->getQuality();
// $quality == 0.81

The CharsetNegotiator returns an instance of AcceptCharset.

Accept* Classes

Accept and Accept* classes share common methods such as:

  • getValue() returns the accept value (e.g. text/html; z=y; a=b; c=d)
  • getNormalizedValue() returns the value with parameters sorted (e.g. text/html; a=b; c=d; z=y)
  • getQuality() returns the quality if available (q parameter)
  • getType() returns the accept type (e.g. text/html)
  • getParameters() returns the set of parameters (excluding the q parameter if provided)
  • getParameter() allows to retrieve a given parameter by its name. Fallback to a $default (nullable) value otherwise.
  • hasParameter() indicates whether a parameter exists.


Negotiation follows Semantic Versioning.

End Of Life


As of October 2016, branch 1.x is not supported anymore, meaning major version 1 reached end of life. Last version is: 1.5.0.


As of November 2020, branch 2.x is not supported anymore, meaning major version 2 reached end of life. Last version is: 2.3.1.

Stable Version

3.x (and dev-master)

Negotiation 3.0 has been released on November 26th, 2020. This is the current stable version and it is in sync with the main branch (a.k.a. master).

Unit Tests

Setup the test suite using Composer:

$ composer install --dev

Run it using PHPUnit:

$ phpunit





Negotiation is released under the MIT License. See the bundled LICENSE file for details.