With the increasing prevalence of middleboxes, networks today are capable of doing far more than merely delivering packets. In fact, to realize their full potential for both supporting innovation and generating revenue, we should think of carrier networks as servicedelivery platforms. This requires providing open interfaces that allow third-parties to leverage carrier-network infrastructures in building global-scale services. In this position paper, we take the first steps towards making this vision concrete by identifying a few such interfaces that are both simple-to-support and safe-to-deploy (for the carrier) while being flexibly useful (for third-parties).