The IFTTT iOS app was updated earlier today with support for rich notifications. In addition to a custom title and image, these rich notifications also support a custom URL that can be opened when a notification is actioned. For example, an applet that notifies you of a new GitHub issue can now include that issue's URL. Tapping the View button in the notification would then open that URL in Safari.
It's also possible to use app URL schemes in notification URLs, so that tapping a notification opens an iOS app—even passing information into it. I created a simple applet, triggered by a button in the IFTTT widget, that sent a rich notification using the new URL scheme of Things as its URL. This URL simply created a new task in my Things inbox, and included some of the default ingredients as the task's note.
IFTTT automatically URL encodes any information passed as an ingredient, though any manually written text must first be URL encoded.
This update narrows the gap between IFTTT and native apps with URL schemes. We're still a long way off an end-to-end solution, since these URL actions can only be triggered when a notification is actioned, and I'm not quite sure how I might use this yet. However, it's still an interesting new way to leverage IFTTT in more apps.