# Knock

> Agentic customer engagement infrastructure for lifecycle and transactional messaging across email, in-app, push, SMS, and chat.

- Website: https://knock.app/?ref=devshelf.io
- DevShelf page: https://devshelf.io/resource/knock
- Pricing: not verified
- Tags: AI-powered
- Categories: [Email & Notification APIs](https://devshelf.io/category/email-notification-apis.md)
- Last checked: 2026-11-03

## About

Knock is an agentic customer engagement infrastructure that allows developers to orchestrate cross-channel messaging flows across email, in-app feeds, push notifications, SMS, and chat. It unifies product, customer data platform, and data warehouse events to trigger dynamic audiences and automated workflows. Features include isolated agent branching, version control via CLI and CI/CD, execution logging, and multi-channel delivery at scale with high availability.

## Alternatives

- [Loops](https://devshelf.io/resource/loops.md): Email sending platform for SaaS teams to manage marketing, product, and transactional emails with API and workflow support. (pricing: Freemium)
- [Customer.io](https://devshelf.io/resource/customer-io.md): A customer engagement platform for automating personalized messaging and lifecycle marketing based on behavioral data. (pricing: Paid)
- [Novu](https://devshelf.io/resource/novu.md): Open-source communication infrastructure to notify users and connect AI agents across multiple messaging channels via a single API. (pricing: Freemium)

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