This article guides you through building an automated notification system for Microsoft Excel and Google Sheets using Twilio Programmable Messaging and SendGrid. The system alerts users when specific, predefined metrics in their data change. It covers setting up the necessary prerequisites, such as a Twilio account and basic programming knowledge, and provides step-by-step instructions for integrating the notification system into your spreadsheet. The article also discusses best practices for setting up an effective notification system and tips for scaling it.