Knock, a notifications-as-a-service platform, transitioned from manually billing customers to adopting a usage-based billing system to streamline their operations and better manage subscription complexities. Initially billing customers manually through Stripe, Knock explored outsourcing this function to usage-based billing providers like Orb, Metronome, Kable, and Lotus, ultimately partnering with Orb due to its user-friendly interface and alignment with Knock's operational needs. The decision was driven by Knock's belief in outsourcing non-core business functions, freeing up resources to focus on product development. Despite challenges such as the cost and effort of integration, the flexibility gained in handling complex billing scenarios and the ability to iterate on pricing models were considered worthwhile investments. The transition involved significant engineering effort, but early results suggest it was beneficial, allowing Knock to efficiently manage customer subscriptions and billing, and enhancing their ability to attract enterprise customers with tailored pricing.