Router::apply()). use Libs\Filter; use Libs\Replacement; use Libs\Router; Router::get('/compat/text/filter', function () { Filter::add( fn (string $content): string => str_replace('mundo', 'MUNDIN', $content), 'compat', 5 ); Filter::add( fn (string $content): string => strtoupper($content) . '|', 'compat', 20 ); echo 'FILTER_OK:' . Filter::apply('hola mundo', 'compat'); }); Router::get('/compat/text/replacement', function () { Replacement::add('/\bfoo\b/', 'bar'); echo 'REPL_OK:' . Replacement::apply('foo y food y foo'); });