We now support App Links through the Extract API endpoint. You will find a list attribute "app_links" in the response that will contain links to Android, IOS, Iphone, etc. apps for the particular web URL when available in the meta tags of the page.
Check out the raw response of this Tumblr post: http://embed.ly/docs/explore/extract?url=http%3A%2F%2Fgracemckendryart.tumblr.com%2F
Also, find more info in this blog post: http://blog.embed.ly/post/84842179751/app-links-support