This document discusses building powerful subscription sites that can scale. It begins by defining subscriptions and discussing the rise of the subscription economy. It then discusses how to scale both technically and from a business perspective. Various ways to implement subscriptions in WordPress are presented, ranging from using off-the-shelf plugins to a bespoke plugin or microservice architecture. Integrating a SaaS solution is presented as allowing for rapid deployment with less development work. Key considerations for choosing a subscription platform include developer friendliness, payment processing, access to data and reporting.