Knock

Knock is a powerful, centralized notification engine designed to decouple notification logic from application codebases. As of 2026, it serves as the industry standard for product teams managing high-volume, cross-channel communication. The platform provides a robust API and a visual workflow builder that allows engineers and product managers to define complex delivery logic, including batching, delaying, and conditional branching across Email, SMS, Push, Slack, and In-app feeds. Technically, Knock operates as an event-driven middleware: applications send a single event to Knock, which then executes a structured workflow to determine the optimal delivery route based on user preferences and provider health. This architecture eliminates the need for maintaining dozens of individual provider integrations (like SendGrid, Twilio, or FCM) and building custom preference centers from scratch. With its 2026 focus on AI-augmented delivery optimization, Knock enables teams to maximize engagement while ensuring strict compliance with global data privacy standards. Its enterprise-readiness is highlighted by SOC2 Type II compliance, high-availability SLAs, and extensive observability tools for monitoring the entire notification lifecycle.