We present Footprint, a system for delivering online services in the increasingly common “integrated” setting, where the same provider operates multiple elements of the infrastructure (e.g., proxies, data centers, and a wide area network). Such integration can boost system efficiency and performance by finely modulating how traffic enters and traverses the infrastructure. We show how such modulation can be practically realized using a model that faithfully captures the complex, time-varying dynamics of service workload. For instance, when a group of users are directed to a new proxy, their ongoing sessions continue to arrive at the old proxy, and this load at the old proxy declines gradually. Footprint is currently being deployed in Microsoft’s infrastructure. Our data-driven simulations show that, compared to the current method, it can carry at least 50% more traffic and reduce user delays by at least 38%.