Gmail Require To – Block Send Without a To Recipient

Blocks sending in Gmail when the To field is empty, even if CC or BCC are filled in.

Ever sent an email with only CC or BCC filled in and nobody in To? Gmail Require To stops that from happening. When the To field of a Gmail message is empty, this extension blocks sending, even if CC or BCC already have recipients. What it does • Greys out the Send button and shows a hint when To is empty • Shows a red notice if you try to send anyway • Also blocks Ctrl+Enter / ⌘+Enter, the schedule-send arrow, and pressing Enter on a focused Send button • Works in multiple compose windows, pop-out windows, and inline reply / forward • Detects the To field by Gmail's structure, not by text, so it works in any Gmail language Privacy • Runs only on mail.google.com • Collects no data, makes no network requests, and needs no extra permissions • Everything happens locally in your browser If Gmail changes its layout and the To field can't be found, the extension lets the email through rather than blocking all sending.