Knock

Knock is a customer engagement platform that centralizes all your product, marketing, and transactional messaging into one system. Instead of stitching together separate tools for email, push notifications, SMS, in-app messages, and chat, you manage everything from a single dashboard. The platform is built for teams that need control: you can design complex messaging journeys, set user preferences, and ensure messages land at the right time across channels.

What sets Knock apart is its focus on developer experience and AI assistance. You can build messaging workflows using natural language prompts — just describe what you want and the AI generates the journey. The platform also offers a CLI that integrates with AI code editors like Cursor and Claude Code, so you can manage notifications directly from your coding environment. Other handy features include version control for your workflows, CI/CD integration to validate changes before deployment, and built-in observability for debugging. Knock supports dynamic audience segmentation based on user attributes and events, and it can ingest data from your warehouse, CDP, or reverse ETL tools.

This tool is ideal for product and engineering teams at mid-to-large companies who want to stop building and maintaining ad-hoc notification systems. Use cases include sending transactional emails (order confirmations, password resets), running lifecycle marketing campaigns, delivering in-app feedback nudges, and managing user preference centers. Teams at Vercel, Medium, and Gorgias use Knock to keep their messaging consistent and reliable without bloating their own codebase.