Push notification system for 3B workflows
Build a self-contained push-notification system: an installable Progressive Web App that lets people subscribe their devices, an ingest endpoint external systems call to raise notifications, delivery of those notifications via Web Push, an acknowledgement callback loop, and an admin audit view. The point is to give any external system a simple way to alert specific people (or broadcast to everyone) on their phones and desktops, and to hear back when an alert is seen or lapses. Trigger it several ways: A browser-facing PWA page (space-authenticated) that users install and open. It registers a service worker, subscribes the device to Web Push, and shows a live history feed that polls for new notifications and lets users acknowledge ones that carry a callback. An ingest HTTP endpoint (protected by an unguessable id, since external systems call it) that accepts a JSON notification — title, body, optional target email, category, tap-through URL, icon, and acknowledgement callback URL. If an email is given, notify only that person's devices; otherwise broadcast to everyone. A scheduled sweeper (runs about every minute) that expires notifications nobody acknowledged in time and fires the source system's callback so it always hears about a lapse. Main pieces to include: The PWA front end (install page + web app manifest + service worker + app icon served as both SVG and PNG, since iOS needs a PNG for home-screen install). A config endpoint that hands the browser the Web Push public key, generating the VAPID key pair lazily on first use and storing it so setup is automatic once published. A subscribe endpoint that stores each browser's push subscription, keyed so re-subscribing overwrites, and tags it with the signed-in user's verified email so notifications can target a person across all their devices. The ingest endpoint that stores each notification, fans the push out to matching subscriptions, prunes dead subscriptions, and records per-recipient delivery status. A list endpoint that returns each user only their own notifications plus broadcasts. An acknowledge endpoint that records who acknowledged and when, then POSTs the acknowledgement back to the notification's callback URL. The scheduled expiry sweeper described above. An admin delivery-log page plus its data endpoint showing the full send history — recipients, timestamps, device counts, delivery status, and acknowledge/expiry state. Use persistent shared storage for subscriptions, the notification log, and the VAPID keys. Keep all browser-facing and admin routes authenticated to the workspace; keep only the external ingest endpoint reachable by outside callers via its unguessable id. Derive the acknowledging/subscribing user from the platform's verified authenticated-email header rather than trusting client input. Handle draft-branch URLs correctly so callbacks and installs work on drafts. Deliver notifications with the standard Web Push protocol and VAPID — or swap in your team's preferred push provider. The acknowledgement and expiry callbacks are plain webhooks, so point them at whatever the source system exposes. Tools used: Web Push (VAPID), service workers / PWA web app manifest, HTTP webhook callbacks
What this prompt builds
A Progressive Web App that enables 3B workflows to send push notifications to users' devices. External systems post notifications via a simple HTTP endpoint, which are then delivered via Web Push to subscribed browsers and phones. The system includes acknowledgement callbacks, automatic expiry handling, and an admin audit log.
The problem
Teams building workflows in 3B need a way to send real-time notifications to people's devices when important events occur. Email and chat platforms are too slow or easy to miss for urgent alerts, and there's no built-in way for workflows to push notifications to phones and desktops. This PWA provides a self-contained push notification system that any 3B workflow can call via a simple HTTP endpoint—users install the app once, and workflows can then alert specific people or broadcast to everyone, with automatic acknowledgement tracking and expiry handling.
Solution and impact
Workflows can now notify the right people within seconds of an event, whether they're away from their desk or not actively monitoring dashboards. The system reduces dependence on email and manual follow-up by delivering alerts directly to devices, enabling faster decision-making on time-sensitive issues. Acknowledgement callbacks and automatic expiry ensure source systems always know whether alerts were seen, making notifications a reliable channel for a wider range of automated processes.