Best of the inbox: the preheader nobody optimizes, optimized

Best of the inbox: the preheader nobody optimizes, optimized
The little gray text after the subject. One operator treated it as real estate and reported the lift.

🧪 Tests
— Custom preheader vs default body-pull: +13% opens — Default preheaders were leaking 'View in browser' and unsubscribe text into the inbox preview. Writing a deliberate second hook lifted opens 13% over 60k sends. Worth your time: they share three preheader formulas that beat the control.
— Hiding it broke a client — A warning worth the read: their zero-width-space trick to hide preheaders rendered as garbage in one app. They reverted; honesty noted.

Made the cut for spotlighting a free, ignored field and disclosing the rendering gotcha.

Saved you ~1 hour and three subject-line tests you didn't need to run first.