diff --git a/inc/Formatting/FieldFormatter.php b/inc/Formatting/FieldFormatter.php
index f86571ac..01a9ebe9 100644
--- a/inc/Formatting/FieldFormatter.php
+++ b/inc/Formatting/FieldFormatter.php
@@ -17,6 +17,11 @@ final class FieldFormatter {
 	 * @psalm-suppress UndefinedClass
 	 */
 	public static function format_currency( mixed $value, ?string $iso_4127_currency_code = null, ?string $locale = null ): string {
+		// The PHP 'intl' extension is not available in WordPress Playground.
+		if ( ! class_exists( 'NumberFormatter' ) || ! function_exists( 'numfmt_create' ) ) {
+			return strval($value);
+		}
+
 		$format = numfmt_create( $locale ?? get_locale(), NumberFormatter::CURRENCY );
 		$currency_code = $iso_4127_currency_code ?? $format->getTextAttribute( NumberFormatter::CURRENCY_CODE );
 		return numfmt_format_currency( $format, (float) $value, $currency_code );