How to Check if a Phone Number is Registered with iMessage Using Google Sheets and the Blooio API

For sales, marketing, and outreach teams, knowing whether a prospect uses iMessage or standard SMS is a game-changer. Delivering a "blue bubble" message gives you access to read receipts, typing indicators, high-quality media sharing, and generally higher engagement rates — features that simply don't exist with regular SMS. But how do you check if a phone number is registered with iMessage across a list of hundreds of contacts without manually typing them into your iPhone? In this tutorial, you'll learn how to build a custom Google Sheets function using Google Apps Script and the Blooio API to automatically detect iMessage availability for any phone number or Apple ID email — at scale. By the end of this guide, you'll be able to type =CHECKIMESSAGE(A2) into any cell and instantly know if that contact is iMessage-ready. Why iMessage Detection Matters for Sales and Marketing Understanding whether your prospects are on iMessage vs. SMS isn't just a nice-to-have — it directly impacts your