September 2022 Summaries

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.

The text explores the development and implementation of a webhook system built on top of Knock's existing notification engine, highlighting best practices and design considerations. A webhook is an API endpoint that facilitates real-time data delivery between web applications. In Knock's system, users configure unique URLs to receive event notifications, such as message status updates, which are delivered through user-defined workflows. The design process was informed by industry best practices and documentation from leading companies like WorkOS and Stripe, focusing on user feedback, event categorization, delivery attempts, retries, and security measures. Knock chose to build its webhook system as an extension of its notification engine, leveraging existing infrastructure for scalability and efficiency. This decision allows for the separation of resources for user and system notifications and provides the potential for future feature expansion. While the architecture introduces some complexity, it simplifies maintenance by relying on a single delivery system and offers opportunities for enhanced functionality, such as exposing webhooks for more complex notifications.

Creating an effective notification system requires more than just delivering messages; it involves orchestrating a seamless, cross-channel user experience and maintaining it as new features and channels are added. Successful product teams either build or purchase systems to manage notification templates and routing logic, incorporating testing, environment versioning, and analytics. The process, known as the product notification lifecycle, includes developing templates and workflows, testing notifications before release, deploying them to production, measuring their effectiveness, and planning for ongoing maintenance. Testing is critical to ensure a positive user experience, while measuring effectiveness helps teams understand notification impact and streamline processes. As notifications become more complex, maintaining visibility and a comprehensive view of all workflows is essential, often requiring internal dashboards or third-party systems like Knock for management. Collaboration across engineering, product, and support teams, with appropriate roles and permissions, ensures effective communication and problem-solving, making the notification system adaptable and robust over time.