Show last post date on bulk sites?

Does anyone know of anything that will show the date of the latest post on a list of URLs? It could pull from example.com/feed or something along those lines. These are all Wordpress sites.

Thanks!

I found one, but it tells me the feed is faulty even though I can see it in a browser. Anyone know of any other site like this? Anyone want to develop one? I'm happy to pay for it.

http://buzzkeep.com/tools/feed-date/