The PHP intl extension (internationalization) ensures websites correctly handle languages, date formats, currencies, and text comparisons per country. Many CMS systems and webshop platforms such as WordPress with multilingual plugins, Symfony, and Magento require this extension. You can activate intl via Plesk by adjusting the correct PHP version settings, without needing server access.
What is the PHP intl extension
The intl extension gives PHP access to the ICU library (International Components for Unicode). This allows an application to, for example, display a date in Dutch, German, or French, format amounts according to local currency notation, and sort text alphabetically according to the rules of a specific language. Without this extension, a script often crashes with an error message such as Class 'NumberFormatter' not found or Class 'IntlDateFormatter' not found.
When do you need intl
You often encounter the error about a missing intl extension in:
- WordPress installations with multilingual plugins such as WPML or Polylang
- Webshops built on Magento or PrestaShop
- Frameworks such as Symfony or Laravel that localize dates and currencies
- Custom PHP scripts that use
NumberFormatter,Collator, orIntlDateFormatter
If intl is not enabled, the installation usually doesn’t work fully, or the admin environment shows an error message when saving settings.
Activating intl in Plesk
At Tandata, you manage PHP extensions directly via Plesk, without a command line or server permissions. The steps below apply to most Plesk environments.
Log in to Plesk
Log in with your Plesk credentials and select the domain for which you want to adjust the extension.
Open PHP settings
Go to Websites & Domains and click on PHP Settings for the relevant domain.
Select the correct PHP version
Check at the top of the page which PHP version is active, so you activate the extension for the correct version.
Check intl
Scroll to the list of available extensions, look for intl, and check the box.
Save the change
Click OK or Apply. The change is activated immediately; a server restart is not required.
Check the result
Create a test file with phpinfo(); or check via your CMS whether the error message has disappeared.
Troubleshooting
If the error message persists after enabling intl, check the following:
- Was the change applied to the PHP version actually used by the domain?
- Does your CMS or hosting configuration have a cache that needs to be cleared first?
- Could a subdomain or add-on domain be using a different PHP setting than the main domain?
If you can’t solve the problem yourself, Tandata’s 24/7 support via WhatsApp, ticket, or email can help you further, even in the middle of the night. More explanations about PHP settings and other server topics can also be found in the knowledge base.
Frequently Asked Questions
Do I need to restart the server after activating intl?
No, in Plesk the change takes effect immediately once you save the setting.
Does this also work for subdomains?
Subdomains can use their own PHP version. Check this separately and activate intl there as well if needed.
Can I also activate intl via .htaccess?
No, intl is a PHP extension that must be loaded server-side; this is managed via Plesk, not via .htaccess.
Why doesn’t my webshop work properly without intl?
Many webshop platforms use intl to format prices and dates per language. If the extension is missing, order processes can get stuck.
Is this feature available with every hosting package?
With web hosting from Tandata, you can manage PHP extensions per domain yourself via Plesk, regardless of the package chosen.
Conclusion
The PHP intl extension is essential for multilingual websites and webshops that want to correctly display dates, currencies, and text per language. Via Plesk, you can easily enable the extension for the correct PHP version, without server permissions or technical knowledge. If you get stuck, Tandata’s support is available day and night.