The most powerful notification system you'll never build
Knock provides flexible, reliable messaging infrastructure that scales with you. Use our APIs to engage users, run workflows, and manage user preferences.
Ship messaging without limits.
Use Knock's notification primitives to build any messaging experience you like, without compromising on design, performance, or user experience.
The New user onboarding workflow in the builder, at Collab.io. An agent step is dragged in from Add a step under the new-user-signup trigger and its prompt is typed: Claude Sonnet 5 writes a welcome line for the recipient that fits their role, into a welcome_line response property. The welcome email greets the recipient by first name, then uses that line. After a 3 day delay, a branch on Created a project? sends a Day 3 tips email to people who have not created one yet and an in-app feed message to everyone else.
Trigger smart automations that send messages across any channel.
email / in-app / push / SMS / chat
Purpose-built for development workflows
Manage messaging the same way you manage code. Develop locally, test across environments, and deploy changes with full version history.
API triggers
Trigger and cancel workflows from the API. Set a schema so invalid data fails before a message reaches a user.
Batch and throttle
Batch a burst of events into one message, or throttle delivery so a user is not notified for every action.
Management API and CLI
Build and promote messaging from your repo. The Management API and Knock CLI fit local and remote workflows.
CI/CD
Validate workflows and templates in CI before they reach production. Catch a bad change on the pull request.
SDKs
Call Knock from Node, Python, Ruby, Go, Java, and more. Official SDKs cover the languages your backend already uses.
Retry logic
Retry a failed send when a provider errors. Knock keeps trying so a transient failure does not drop the message.
Advanced preferences
Set preferences from your own UI or Knock's hosted center. Group choices by channel, workflow, or category.
Send windows
Deliver each message inside the hours a recipient expects. Hold anything outside the window until the next open time.
Translations
Localize email, in-app, and other channel copy per locale. Ship one workflow in every language.
Bring your application's data into Knock.
Connect warehouse, CDP, and application data to Knock, model it with custom objects, and trigger workflows directly from API calls.
Product usage from the Knock SDKs, traits from a CDP such as PostHog, Segment, or Amplitude, account data synced by Hightouch from a warehouse such as Snowflake, Databricks, or BigQuery, and billing data from Stripe flow into one user model in Knock as user properties.
A dynamic audience updates as those properties change, and a user entering the audience triggers a workflow.
Make changes without impacting production.
Debug every run and stream logs to your own tooling. Roll back a change with a click.
An agent's branch forks off main in coral. A person merges it and publishes it, and the change turns ink and goes live, where every run is logged and any version can be reverted.
Work on a branch
Agents work in isolation, not on your live messaging.
Merge and publish
A person reads the diff, then merges and publishes it.
Monitor every run
Logs show details for every step of every run.
Analyze performance
Measure the impact of your messaging across channels.
Manage from your repo
Merge and promote from the Knock CLI and CI/CD.
Messaging infrastructure you can trust
99.99% uptime
We run Knock as critical infrastructure for your product.
Scaled delivery
Knock delivers hundreds of millions of messages per month.
Dedicated success
Our team helps you plan, build, and launch your messaging.
Secure access
Security is standard with support for SSO, RBAC, and SCIM.
HIPAA
SOC2
GDPR
CCPA
Trusted in production at
“Notifications at scale”
Notification infrastructure is the most essential part of any product that I'd never dare build myself from scratch or operate at scale. Knock's APIs allow me to focus on my front-end experience, while all the complexity is abstracted away.
Founder + CEO • Vercel
Frequently asked questions
Yes. Engineering teams use Knock for email, SMS, push, chat, and in-app, with workflows, templates, and preferences behind one API.
Yes. Trigger a workflow with a typed payload, and cancel it when the user completes the action. A schema rejects invalid data before send.
Yes. The Management API and Knock CLI let you develop locally and validate changes in CI before they reach production.
Yes. Guides and feed hooks render with your components, so the UI stays on your design system.
Official SDKs include Node, Python, Ruby, Go, Java, .NET, Elixir, and PHP.
Logs show each step of each run. Stream them to your observability tooling, and roll back a bad change without a deploy.