This is a simple Heroku PHP app showcasing how to install Composer packages. It simply takes strings and converts them to clean URL names.
Creating such an app is easy. Simply set it to use the custom PHP buildpack until the changes are accepted into the official one:
$ heroku create -s cedar --buildpack https://github.com/bergie/heroku-buildpack-php.git urlizer-service
And then deploy:
$ git push heroku master
You can see an example at Heroku