Writing
AI Prompt for Email Subject Lines
Write subject lines people open: this AI prompt creates 25 options across curiosity, benefit, and urgency styles — all under 50 characters. Try it today.
The prompt
You are an email copywriter obsessed with open rates. Context: I am writing an email about [EMAIL_TOPIC] to [AUDIENCE]. The one action I want readers to take is [DESIRED_ACTION]. The brand voice is [TONE]. Task: Write 25 subject line options, grouped into 5 styles with 5 each: curiosity gap, direct benefit, urgency/scarcity, personal/story, and question. Then write 5 matching preview-text lines (the snippet after the subject) for your 5 favorite subject lines. Rank your top 5 subject lines overall and give a one-line reason for each ranking. Format: Grouped numbered lists. Bold the top 5 at the end with reasons. Keep preview texts on the same line as their subject line, separated by a dash. Constraints: Every subject line must be under 50 characters to survive mobile inboxes. No spam-trigger words like "FREE!!!", "guaranteed", or "act now". No misleading subjects — the subject must match the email content. Avoid excessive punctuation and ALL CAPS.
Variables to fill in
Replace each [variable] in the prompt with your own details:
[EMAIL_TOPIC] [AUDIENCE] [DESIRED_ACTION] [TONE]
Example input
Example: EMAIL_TOPIC = 'new beginner photography course', AUDIENCE = 'hobby photographers', DESIRED_ACTION = 'click through to the course page', TONE = 'friendly expert'.
How to use this prompt
Pick your top 2 subject lines and A/B test them on a small segment before sending to your full list — even a 2% open-rate lift compounds fast.
Tips for the best results
- Pair every subject line with preview text — it's free extra persuasion.
- Test curiosity vs. benefit styles; audiences split hard on this.
- Avoid repeating the same style two emails in a row to prevent fatigue.
Frequently asked questions
Do emojis in subject lines help?
Sometimes, for casual audiences. Test with your list — they can lift opens or look spammy depending on the audience.
How long should preview text be?
Aim for 40-90 characters so it displays fully on most phones and desktops.