: It includes a "read receipt" feature that can be toggled to notify you the moment a recipient engages with your content. 3. Instantly.ai - Server-Level Reliability

A dedicated Chrome extension designed to work directly within the Yahoo Mail interface, providing real-time open notifications.

Log into your Gmail account and go to Settings > See all settings > Accounts and Import .

: It is a Chrome extension that integrates directly into the Yahoo webmail interface.