Trigger Nodes

Trigger nodes start workflow execution. Every flow must begin with exactly one trigger.

Available Triggers

Interface Event Trigger

The primary way to create backend functions callable from your frontend via callFlow() or executeFlow().

Configuration:

Input Parameter Format:

{
  "inputParams": [
    { "name": "email", "type": "string", "required": true },
    { "name": "category", "type": "string", "required": false }
  ]
}

Supported Types: string, number, boolean, object, array

Accessing Input Data:

• {{ $input.fieldName }} - Access a specific input field
• {{ $input }} - Access the entire input object

Example Flow:

{
  "id": "interface_event_trigger-1",
  "type": "interface_event_trigger",
  "label": "Get Products",
  "config": {
    "inputParams": [
      { "name": "category", "type": "string", "required": false }
    ]
  }
}

Calling from Interface:

// Server-side (in page.tsx)
const products = await executeFlow('get_products', { category: 'electronics' });
 
// Client-side (in 'use client' component)
const result = await callFlow('get_products', { category: 'electronics' });

Webhook Trigger

Receive HTTP requests from external services (Stripe, GitHub, Zapier, etc.).

Configuration:

Output Variables:

• {{ $input.body }} - Parsed request body (JSON)
• {{ $input.headers }} - Request headers object
• {{ $input.query }} - URL query parameters
• {{ $input.method }} - HTTP method (POST, GET, etc.)

Example:

{
  "id": "webhook_trigger-1",
  "type": "webhook_trigger",
  "label": "Stripe Webhook",
  "config": {
    "respondImmediately": false
  }
}

Getting Your Webhook URL:

node bin/lux-cli/lux.js workflows webhook-url <flow-id>

Use Cases: Payment webhooks, GitHub events, form submissions, IoT events.

Schedule Trigger

Run workflows on a recurring schedule.

Configuration:

Output Variables:

• {{ $input.triggeredAt }} - ISO timestamp when triggered
• {{ $input.scheduleName }} - Name of the schedule

Examples:

Every 5 minutes:

{
  "scheduleType": "interval",
  "intervalValue": 5,
  "intervalUnit": "minutes"
}

Daily at 9am:

{
  "scheduleType": "daily",
  "dailyTime": "09:00",
  "timezone": "America/New_York"
}

Cron (weekdays at 6pm):

{
  "scheduleType": "cron",
  "cronExpression": "0 18 * * 1-5"
}

Manual Trigger

Start workflows manually with custom input data. Useful for testing and admin operations.

Configuration:

Example:

{
  "id": "manual_trigger-1",
  "type": "manual_trigger",
  "label": "Manual Start",
  "config": {
    "inputParams": [
      { "name": "userId", "type": "string", "required": true },
      { "name": "action", "type": "string", "required": true }
    ]
  }
}

Inbound Call Trigger

Trigger workflow when a phone call is received on your Twilio number.

Configuration:

Output Variables (after call completes):

• {{ $input.callSid }} - Twilio call SID
• {{ $input.from }} - Caller's phone number
• {{ $input.to }} - Called phone number
• {{ $input.transcript }} - Full conversation transcript
• {{ $input.data_collection_results }} - Collected data from the call
• {{ $input.call_duration_secs }} - Call duration in seconds

Example:

{
  "id": "inbound_call_trigger-1",
  "type": "inbound_call_trigger",
  "label": "Support Line",
  "config": {
    "phoneNumberId": "PNxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    "agentId": "agent_abc123"
  }
}

Setting Up:

# List Twilio numbers
node bin/lux-cli/lux.js voice-agents twilio-numbers
 
# Configure inbound handling
node bin/lux-cli/lux.js voice-agents configure-inbound +15551234567 <flow-id>

SMS Received Trigger

Trigger workflow when an SMS message is received on your Twilio number.

Configuration:

Output Variables:

• {{ $input.message_body }} - The SMS message content
• {{ $input.sending_number }} - Phone number that sent the SMS
• {{ $input.receiving_number }} - Your Twilio number
• {{ $input.received_timestamp }} - When the message was received (ISO 8601)

Example:

{
  "id": "sms_received_trigger-1",
  "type": "sms_received_trigger",
  "label": "SMS Auto-Responder",
  "config": {
    "phoneNumber": "+14155551234"
  }
}

Expression Syntax Reference

Access data in your flows using these patterns:

See Also:

• Flows Overview
• Data Nodes
• Voice Agents