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

🔄 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

Open the ‘Set’ node where you map Vapi parameters. 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). (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

🎨 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).

📇 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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