Knock
Knock
Role
Notification orchestration — the family's single workflow engine for cross-channel notifications. One Knock workflow per event type (billing receipt, password change, comment reply, feature rollout) fans out to the right channels in the right order, dedupes within a window, and surfaces in-app + email + SMS + web push from one place.
Knock does not replace FCM — FCM stays as the transport for the web-push channel. Knock's web-push provider config points at our Firebase project. Knock owns scheduling, batching, channel selection, and per-user preference; FCM owns "actually push to the browser." Same split for email (Resend is the SMTP transport behind Knock's email channel).
Free tier
- 10,000 notifications/month
- Unlimited workflows + recipients
- All channels — in-app, email, SMS, web push, Slack, Microsoft Teams, Discord
- 30-day notification log retention
- Branch-based environments (dev / staging / prod)
- Per-user preference center, quiet hours, digest windows
Card / subscription required?
NO. Free-tier sign-up is email-only. No payment method requested. Stays free as long as monthly volume stays under 10K notifications across all channels.
What runs through Knock
- Billing receipts — Razorpay / Lemon Squeezy webhook → Hono Worker → Knock workflow → email + in-app + (optional) SMS
- Password / passkey changes — Firebase Auth event → Worker → Knock workflow → email + SMS + web push
- Comment-reply notifications — Firestore trigger → Worker → Knock workflow → web push (FCM) + in-app
- Feature rollout pings — Hypertune flag flip → Knock workflow → in-app + opted-in web push
Channel mapping
| Channel | Transport | Why Knock + transport split |
|---|---|---|
| Web push | FCM | FCM is free unlimited on Spark + iOS PWA support |
| Resend | Resend already wired for transactional | |
| SMS | Knock-bundled (Twilio / MessageBird) | Pay-per-SMS only, no monthly fee |
| In-app feed | Knock-hosted | Drop-in <KnockFeed /> component |
| Slack | Knock direct | Used for ops alerts only |
Alternatives
- Courier — free 10K notifs/mo, similar model
- Novu — open-source, self-hostable; rejected per
- Customer.io — paid only past 200 contacts
- Building it ourselves on Workers — re-implementing dedupe, digest, preference center, channel routing is months of work
Swap cost
Medium — Knock workflow definitions live as YAML in the Knock dashboard; export-to-JSON is supported. Swapping means recreating workflows in Courier or similar. Channel transports (FCM, Resend) do not change, so the Worker-side code stays the same.
Why this is our pick
Free 10K/month is generous — the family's combined notification
volume across 11+ sites is well under that. The orchestration model
fits how we think about notifications (one event → many channels),
and it leaves FCM and Resend doing what they're best at. The
in-app feed component drops in as <KnockFeed /> — saves us
building a notification center in @chirag127/oriz-kit.