Flash Sale Subject Lines: 5 Examples (and a Free Tester)

Flash sales run on real, ticking urgency. The subject's job is to make 'open now or miss it' obvious without tipping into spam-filter territory.

5 flash sale subject line examples that work

• 6 hours. then it's gone.24 chars
• flash sale — starts now23 chars
• blink and you'll miss this26 chars
• ends at midnight (for real)27 chars
• quick — 30% off until 5pm25 chars

Rules for flash sale subject lines

• State the window clearly ('6 hours only').
• One exclamation max — filters punish flash-sale shouting hardest.
• Put the clock in preview text to reinforce the subject.
• Resend to non-openers near the deadline with a new angle.