Signals

Signals are named events that can be fired and listened to within the Virbe pipeline. They provide a flexible communication mechanism between flows, between the pipeline and external systems (like the embedding website or SDK), and across the conversation lifecycle.

How Signals WorkCopy Anchor Link

When a signal fires, any node in the pipeline that is listening for that signal can react to it. Signals are not routed automatically – you connect signal-aware nodes (like Route by Signal and Signal Handler) to handle specific signals within your logic.

Signals carry a name and an optional value (metadata sent with the signal).

Opening the Signals PanelCopy Anchor Link

Click Signals at the bottom of the left sidebar to open the Signals panel. The panel shows all signals available in this pipeline – both predefined system signals and any custom signals you have created.

Predefined SignalsCopy Anchor Link

Four signals are built into every pipeline and cannot be deleted. They map to the core conversation lifecycle events:

These predefined signals are what trigger the corresponding Handlers (On Language Change, On conversation-start, On conversation-stop, On face-detected).

Custom SignalsCopy Anchor Link

You can create your own signals for any purpose – typically for communicating between the embedding website/app and the pipeline, or between flows.

Creating a Custom SignalCopy Anchor Link

1. Open the Signals panel
2. Click + Create new signal
3. Enter a Name (e.g., product-scanned, user-authenticated, checkout-started)
4. Enter a Description for your own reference
5. Click Create

Custom signals can be:

• Fired from the embedding website or app using the Virbe JS SDK (passing the signal name and an optional value)
• Received in the pipeline via Route by Signal or Signal Handler nodes
• Triggered by external devices like barcode or QR code scanners

Naming ConventionsCopy Anchor Link

Signal names are lowercase and hyphen-separated by convention (e.g., product-selected, qr-code-scanned). Keep names descriptive and specific.

Using Signals in FlowsCopy Anchor Link

Route by SignalCopy Anchor Link

The Route by Signal node branches the flow based on which signal is currently active. Use it when a flow needs to behave differently depending on how it was triggered.

Flow Entrypoint
    │
    ├── On User Input ──► [handle user message]
    │
    └── On Signal ──► Route by Signal
                          ├── product-scanned ──► [product lookup flow]
                          ├── qr-code-scanned ──► [QR handler flow]
                          └── default ──► [generic signal handler]

Signal Handler (in Handlers)Copy Anchor Link

Each Handler entry node exposes an On Signal branch, which fires when the Handler is triggered by a signal rather than a direct user action. This is used in Handlers like On Language Change to distinguish between speech-detected changes and programmatically fired signals.

Sending Signals from External SourcesCopy Anchor Link

If your virtual being is embedded on a website or in an app, you can fire signals from the surrounding page using the Virbe JavaScript API. This lets the website communicate directly with the pipeline – for example, sending a product-selected signal when the user clicks a product on the page.

// Example: fire a signal from the embedding page
virbeWidget.sendSignal('product-selected', { productId: '12345' });

The signal name and value are available inside the pipeline via the Signal Name and Signal Value fields (accessible through the Insert field picker).

Best PracticesCopy Anchor Link

• Use predefined signals for lifecycle logic – don't create custom replacements for conversation-start or conversation-stop.
• Keep custom signal names specific and meaningful – checkout-abandoned is clearer than event-1.
• Document what each custom signal is for in its Description field.
• Use signals for loose coupling between the embedding page and the pipeline – they are better than tightly coupling business logic to specific flow names.

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