Knock Notifications Platform

Knock is a notifications-as-a-service platform founded by Chris Bell and Sam Thiel in 2022, backed by investors including Andreessen Horowitz and Heavybit, providing a unified API for managing and delivering notifications across multiple channels including email, SMS, push notifications, in-app messages, and chat messages through Slack and Microsoft Teams, with features including visual workflow builder, template management, user preference management, delivery throttling, batching, digest schedules, content rendering, and delivery tracking, designed to abstract the complexity of integrating multiple notification providers into a single, developer-friendly API, adopted by companies including Vercel, Linear, and Orbit for their notification infrastructure. The workflow builder provides a visual, no-code interface for designing notification workflows, with each workflow consisting of triggers, conditions, channels, and steps, enabling product teams to create complex notification logic including conditional delivery based on user attributes, channel fallback when primary channels fail, time-based throttling to prevent notification fatigue, message batching to group related notifications, and digest schedules that summarize multiple notifications into periodic summaries, all without code changes. The cross-channel delivery integrates with over fifteen notification providers including SendGrid and Postmark for email, Twilio and MessageBird for SMS, Firebase Cloud Messaging and Apple Push Notification Service for mobile push, OneSignal for web push, and Slack and Microsoft Teams for chat, with the platform automatically handling provider-specific formatting, rate limits, and error retries. The user preference center for managing notification opt-ins. The template engine with Liquid syntax. The delivery tracking and analytics. The REST API. The webhooks. Designed by Chris Bell. Designed for product and engineering teams.