This is the plugin to generate short URL. This plugin is based on Google API for URL shortener. TBM Google URL Shortener will display a form to your website from where your website visitors can enter the long URL to make them short.
You need a Google API Key to configure this plugin. Here are few useful links for Google API Key:
Get API Key: https://developers.google.com/url-shortener/v1/getting_started#APIKey
Learn more about API Key: https://developers.google.com/url-shortener/v1/getting_started#auth
Check Demo: http://www.thebestmakers.com/tbm-google-url-shortener