Run a Unified App
Engine automatically invokes your deployed TypeScript with the event payload. Call selected services, save processed results, and inspect the run in Requests. No separate receiver process is needed.
Service events, ready for action
Turn events into action.
A payment clears. An issue changes. Fused receives the event and routes it to the apps you choose: run a Unified App in Engine, handle it in your backend, or give an agent fresh context through MCP.
Register the source. Select the events. Choose what happens next.
Event sourceStripePayment confirmed
Fused Engine
Verify Queue RouteChoose the destination Unified App · run logic Backend · SDK receiver Agent · MCP resource
Only selected events reach each app
Choose how to respond
One event. Three ways to use it.
Create a registration from the Webhooks page or CLI, then attach it to an app and select its events. Connect the provider to a Fused webhook URL, or use an available managed event connection.
Handle it in your backend
A generated SDK receiver delivers selected events over an outbound connection. Durable, at-least-once delivery and acknowledgements let your backend handle each occurrence without its own public webhook endpoint.
Give agents fresh context
MCP clients can listen for event-resource updates and read the latest retained payload. The client decides when the agent acts. Missed notifications are not replayed; use a durable receiver to handle every occurrence.
Three modes, in code
Choose where the response runs.
Hosted event handler
import * as z from "zod/mini";
import { buildUnifiedApp, fused } from "@fused/unified-app";
const issue = z.object({ id: z.string() });
export default buildUnifiedApp({
input: z.object({ body: z.object({ issue }) }),
output: z.object({ issueId: z.string() }),
fetch: { searchable: ["issueId"] },
// Keep a searchable result from the incoming event.
async execute({ input }) {
const issueId = input.body.issue.id;
await fused.db.set({ issueId });
return { issueId };
},
});Run inside Engine
The event becomes execute() input. This app saves the issue ID and returns a result.
Before you run it
Attach an applied webhook registration and select issue.created in your Unified App config. Match the input schema to the selected provider event.
Engine starts the consumer after deployment. Results and saved data are retained for 24 hours.
Event → Unified App → result
Let the event run the integration.
Attach provider events to a Unified App and deploy it. Engine starts the consumer automatically and runs your reviewed code when a selected event arrives.See Unified App codeThe event runs your logic
Read the normalized event from input.body
Call the service operations your app selects
Choose processed data to save with the run
See the outcome
Trace the run to its source event
Inspect status, timing, and provider calls
Retrieve results and saved data for 24 hours
SDK delivery can repeat an event, so handlers should be idempotent. Unified Apps retain authored failures for inspection rather than automatically repeating provider effects. Raw diagnostics require the relevant permission.