Not sure if you mean this page or not: https://www.phusionpassenger.com/ https://www.phusionpassenger.com/ But as they say, it's an application server. Similar

Not sure if you mean this page or not: https://www.phusionpassenger.com/ https://www.phusionpassenger.com/ But as they say, it's an application server. Similar to mod_perl for apache/php, unicorn or indeed nodejs (which can function as an application server for Javascript).