Automate Outbound Voice Calls with Vapi from Form Submissions

This n8n automation connects your n8n form submissions to Vapi AI, enabling you to immediately call new respondents with a personalized voice AI assistant, as soon as the form is submitted.

🧾 Requirements

n8n Form

• An n8n form node published and accessible to users.
• The form must include a phone number field:
  • Accept full international phone number with + and country code.
    Example: +11234567890
• (Optional) Add more form fields as needed for your use case.

Vapi

• A Vapi account with credit.
• A connected phone number for outbound calls.
• An assistant created and ready to make calls.
• Your Vapi API key.

🔗 Useful Link

• Vapi calll endpoint

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🔄 Workflow Breakdown

1. Trigger: Form Submission (n8n Form)

• Starts when a submission is received from your form.

2. Wait 2 Minutes

• Inserts a 2-minute pause before the next steps.

3. Set Vapi Fields (Manual Step)

Step-by-Step: Configuring Vapi Parameters in the ‘Set fields’ Node

1. Open the ‘Set’ node where you map Vapi parameters.
2. Add fields (if not present):
   • phone_number_id: The sender phone number ID from your Vapi dashboard.
   • assistant_id: The ID of the Vapi AI assistant you want to use.
   • api_key: Paste your Vapi API key here (keep secure).
3. (Optional) Add more fields for personalization, such as:
   • first_name, product, reason, etc., if captured in your form.

4. Start Outbound Vapi Call

• Sends a POST request to https://api.vapi.ai/call.
• Payload includes:
  • Phone number from form
  • Chosen assistant ID
  • Vapi number ID
  • Any additional info you choose to pass for customizing the call

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🎨 Customization

How to Adapt for Different Use Cases

• Collect More Info:
  Add fields to your n8n form for details such as name, product type, issue/context, preferred language, etc.
• Use Extra Data in Calls:
  In the HTTP request node, pass these fields in the API request body to Vapi. Tailor your assistant’s script to reference these for a personalized experience.
• Conditional Calls:
  Add n8n logic nodes to filter/categorize submissions (e.g., only call if a checkbox is ticked or if value matches certain criteria).
• Dynamic Assistant Selection:
  Select assistant or Vapi number based on user responses (e.g., route to different assistants by region or requested service).

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📇 Using Additional Form Fields in Vapi Calls

• Any field collected on your n8n form can be included in the call payload, simply add it in the HTTP request payload.
• Vapi can use these variables for dynamically constructing prompts, personalizing the call flow, or branching logic in the interaction.
• Example: If your form collects first_name and appointment_time, both can be sent to Vapi and referenced in the call script or as variables in your assistant’s logic.

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