Return Google Sheets caller data to Retell inbound call webhooks

## Handle Retell's Inbound call webhooks ## Overview - This workflow provides Retell agent builders with a simple way to populate dynamic variables ## How it works - The webhook call is received from Retell. We filter the call using their whitelisted IP address. - It extracts data from the webhook call and uses it to retrieve the user from Google Sheets. - It formats the data in the response to match Retell's expected format. - Retell uses this data to replace dynamic variables. - Copy the Webhook URL (e.g., {{ $env.WEBHOOK_URL }}) and paste it into Retell's interface. Navigate to "Phone Numbers", click on the phone number, and enable "Add an inbound webhook". - In your prompt (e.g., "welcome message"), use the variable with this syntax: {{variable_name}} (see [Retell's documentation]({{ $env.WEBHOOK_URL }} - These variables will be dynamically replaced by the data in your Google Sheet. ## Notes - In Google Sheets, the phone number must start with '+'. - Phone numbers must be formatted like the example: with the +, extension, and no spaces. - You can use any database—just replace Google Sheets with your own, making sure to keep the phone number formatting consistent.