Missed Call SMS Auto-Reply with GPT-4o, Twilio & n8n

Turn missed calls into SMS replies—automatically

Missed Call SMS Auto-Reply with GPT-4o, Twilio & n8n automatically receives missed-call webhooks, drafts a personalized SMS text-back with OpenAI (GPT-4o), sends it via Twilio, and logs every “rescue” to Google Sheets while notifying you in Slack.

What this workflow does

• Receives missed/unanswered call events: A POST webhook triggers the workflow when your phone system reports a missed or unanswered call.
• Normalizes the payload and avoids false replies: The workflow normalizes incoming call details from common formats (including Twilio, CallRail, or 3CX) and stops if the call status indicates it was answered.
• Drafts a personalized SMS with GPT-4o: It sends caller details and your provided business context to OpenAI to generate a short, personalized text-back.
• Routes and sends the SMS via Twilio: Based on your configured sendMode, the workflow routes the SMS for owner review or sends it directly to the caller using your Twilio phone number.
• Logs and alerts: It appends the event details and drafted message to Google Sheets and posts an alert to your Slack channel.

Use cases

• Local service businesses: Missed calls become immediate SMS follow-ups with a booking link.
• SaaS teams with phone support: Capture lost leads instantly and send a text-back requesting the next best time to connect.
• Agencies & call-tracking setups: Work with Twilio, CallRail, or 3CX payloads and keep a clear audit trail in Google Sheets.

Technical details

• Integrations / nodes: webhook, set, code, sticky note, OpenAI (GPT-4o), Twilio, Slack
• Optional storage: Google Sheets for logging missed-call events and drafted SMS content
• Setup highlights: Configure your phone system webhook URL, update Settings (business name, owner mobile, Twilio number, booking link, sendMode, business context), add Twilio + OpenAI credentials, and (optional) add Google Sheets + Slack credentials.