Knock

Knock is a developer-first notification infrastructure platform that provides APIs and tools for sending cross-channel product and customer messaging. Rather than being a traditional email marketing platform, Knock specializes in transactional notifications, product messaging, and lifecycle communications that can be triggered programmatically across email, SMS, push notifications, in-app feeds, and chat platforms like Slack and Teams.

The platform offers a comprehensive notification system with workflow orchestration, dynamic template builders, multi-channel messaging capabilities, and advanced user preference management. Features include drag-and-drop email builders, code-based template editors, batch processing, conditional logic, A/B testing, real-time in-app notification feeds, and integrations with major providers like SendGrid, Postmark, AWS SES, Twilio, and others. Knock's developer-focused approach includes CLI tools, environment management, and version control integration.

Ideal for SaaS companies, mobile apps, and product teams that need to send transactional and product-driven notifications rather than traditional marketing campaigns, Knock serves developers and product teams looking for programmatic control over customer communications. The platform is particularly valuable for companies requiring real-time, event-driven messaging with complex logic, multi-channel orchestration, and production-grade reliability for user-facing notifications.