URL categorization in a Chrome Extension

I have a Chrome extension that records the date, time spent, and url of sites visited in a popup window. I would like to categorize the urls into five (or more) basic categories and place that category in the popup. I have seen web categorization APIs online. However, perhaps this is more simple than that. I just want to scan the url and then pretty much attach a label to it and display it. For example, anything with the word store in it could be categorized as “Retail” or .gov as “Government”. What is the best way to do this?

Chrome extension API for web categorization

I have a Google Chrome extension that generates a popup with the following data:
date, time spent, url. I would like to know how to automatically categorize the url and place that in my popup. I can see that there are many free web categorization APIs online but I am not sure which would be appropriate for a Chrome extension. Please advise what API might be the best choice for this application.