Where is the intl PHP extension? Problem solved!

Problem

PHP packages/frameworks/libraries/scripts we work with might require different PHP extensions. In this case the Intl extension is needed to work with using Internationalization Functions. What is Internationalization? Got any of these error messages?

• Zend InputFilter requires intl PHP extension
• The requested PHP extension intl is missing from your system

  This happened because the PHP Intl extension isn't installed or enabled. Parts of this tutorial can be also a guide for installing or enabling other extensions.

What is PHP Intl?

Internationalization extension (further is referred as Intl) is a wrapper for » ICU library, enabling PHP programmers to perform various locale-aware operations including but not limited to formatting, transliteration, encoding conversion, calendar operations

Source: PHP Documentation

This extension may be installed using the bundled version as of PHP 5.3.0, or as a PECL extension as of PHP 5.2.0. In other words, there are two methods to install the intl extension.

Source: PHP Documentation

Cause

If you have installed the unbundled PHP version, the extension is not installed on the system. (unless you've installed it separately) If you have the bundled PHP version, the extension might be existing but not enabled.  

Solutions

For Linux-based Server (assuming you have root access):

• Make sure the php_intl.so file exists within your php extensions directory, find the extensions directory by:
  • using phpinfo()
  • running this command: php -r "echo ini_get('extension_dir');"
  • (note: both options gets the extension_dir right from the PHP runtime configuration)

• If the file exists:
  • search for the config file (php.ini, usually /etc/php.ini) and open it
  • Make sure the line "extension=php_intl.so" is existing and not commented
  • Restart the web server (usually sudo service httpd restart)
  • Check if the extension is enabled using phpinfo()
• If the file doesn't exist
  • Check your php version by running the "php -v" command
  • For PHP 5 install the php-intl package using your package manager - package managers and commands
    • Most common: apt-get install php-intl (for ubuntu-based linux) or yum install php-intl (for CentOS)
  • For PHP 7, install the php7.x-intl (depending on your php version)
  • Repeat the steps for the case in which the file exists

For projects hosted on a shared hosting platform you must ask your hosting provider to install/enable the PHP Intl extension.  

For Windows-based Server:

• Make sure the php_intl.dll file exists within your php extensions directory
  • for separately installed PHP: C:\path\to\php\ext\
  • for xampp: C:\path\to\xampp\php\ext
  • (note: your drive letter might be different)

• If the file exists:
  • search for the config file (php.ini, usually in the same folder as the php executable) and open it
  • Make sure the line "extension=php_intl.dll" is existing and not commented
  • Restart the web server (usually apache)
  • Check if the extension is enabled using phpinfo()

• If the file doesn't exist:
  • Check your php version by running the "php -v" command
  • Download the PHP version that corresponds to yours from the PHP Downloads Page (TS/NTS, x86/x64)
    • To find thread safety for php, run: php -i | findstr "Thread" , source & more info.
  • Search for the php_intl.dll file in the ext folder in that version and copy it in your php\ext folder
  • Repeat the steps for the case in which the file exists

Edit: changed php7.0 occurrences with php7.x as the version may vary.

Frequently Asked Questions