How Medium turned notifications from an engineering bottleneck into a growth engine

Medium, a widely-used publishing platform with over 100 million monthly readers, faced significant challenges with its custom-built notification system, which required extensive engineering time and hindered growth experiments. To overcome these barriers, Medium implemented Knock, a platform that drastically reduced the time needed to deploy new notifications and enabled marketing and product teams to operate independently without constant engineering involvement. Knock's capabilities allowed Medium to launch more sophisticated and efficient email and push notification campaigns, such as their high-converting Black Friday push notification, and introduced a unified email design system to maintain brand consistency. This strategic shift transformed notifications from a resource-heavy bottleneck into a vital growth tool, enabling Medium to innovate rapidly and enhance user engagement and retention.