Webhooks MQTT and iCal

Webhooks, MQTT & iCal

Beyond simple queries, the bridge can push your inventory into other systems — fire webhooks on changes, publish over MQTT, and serve a calendar feed. Each is a separate opt-in.

ℹ️ Note These are technical integrations. Exact configuration is in the bridge README in the Gubbins repository; this page explains what each is for.

Change events: webhooks & SSE

The bridge can emit change events — an item's stock went low, something was added, a loan came due. Two ways to consume them:

• Webhooks — the bridge calls a URL you provide when something happens, so another system can react.
• SSE event stream — a live stream you can subscribe to for a running feed of changes.

Both are off until you enable them.

MQTT publishing & Home Assistant discovery

The bridge can publish to an MQTT broker — including summary topics like stock counts — and announce them via Home Assistant MQTT discovery, so they show up as entities automatically. See Home Assistant integration.

Calendar feed (iCal)

The bridge serves a read-only iCalendar feed of Gubbins' time-bearing facts — loan due-backs, bookings, maintenance and warranty dates — that any calendar app can subscribe to. Your Gubbins deadlines then sit alongside the rest of your schedule, updating as your data changes.

💡 Tip The calendar feed is the easiest of these to use — subscribe to it from your phone or desktop calendar and every Gubbins due-date appears automatically, no automation required.

⚠️ Heads-up These surfaces can send your data outward (to a webhook target, an MQTT broker, a calendar service). Each is opt-in, token-protected, and best kept to trusted destinations and your local network. See Privacy & security.

Related pages

• Bridge overview and Running the bridge — the foundation.
• Home Assistant integration — MQTT discovery in context.
• Upcoming agenda — the in-app view of the same deadlines the iCal feed publishes.