Use this by goal, not as a fixed script. A subject line's job is one thing: make the right person open. Pick the bucket that matches your email, then drop in your details.
Curiosity (no clickbait)
The [number] mistake most [audience] make with [topic] A simpler way to [outcome] (that actually works) What [successful example] does differently with [topic]
Direct benefit
[Number] [things] that [outcome] in [timeframe] Get [outcome] without [common pain] Your [goal] just got easier
Personal / segmented
[Name], [specific reason] this is for you Saw you [action] — here's [help] [Segment], here's your [resource]
Urgency (honest only)
[Number] spots left for [thing] Ends [date]: [what they lose] Last call — [outcome] before [deadline]
Spam-trigger words to avoid
- ALL CAPS and excessive punctuation (!!!)
- "FREE!!!", "100% guaranteed", "act now", "click here"
- Mixtures of numbers and symbols that look like promotions
- Any claim you can't honour — it hurts deliverability and trust
Need full email drafts?
From subject to sign-off, here is the sequence workflow we use.
See the sequence →What do people ask about 50 Email Subject Line Templates?
How long should a subject line be?
Roughly 30–50 characters. Mobile previews cut off around 30–40, so front-load the point.
Are emojis in subject lines good or bad?
They can lift opens when relevant, but overuse looks spammy. Test one per send, never a row of them.
What words hurt deliverability most?
ALL CAPS, multiple exclamation marks, and hard-sell words like 'free', 'guaranteed', 'act now'.
Can an AI writer generate subject lines?
Yes — give it the goal and audience and ask for ten variants, then pick the most honest and specific.