UNDO for Outlook Web is a free Chrome extension designed to enhance email management by adding a brief delay before sending emails. This feature allows users to reconsider their messages after clicking the Send button or using keyboard shortcuts like Ctrl/⌘+Enter. The extension presents an undo option during this pause, enabling users to cancel the send action or proceed with immediate delivery. This functionality is particularly useful for those who want to avoid sending emails in haste and need a moment to reflect on their communication.

The extension operates solely within the Outlook Web platform, ensuring a seamless integration without any external dependencies. UNDO runs locally in the browser, prioritizing user privacy by not reading email content, storing data, or connecting to external servers. As a standalone tool, it provides a straightforward solution to improve email sending practices without bundling additional software or products.