Generator · 100% free, no signup · Updated May 2026
10 subject lines per email, sized for inbox preview.
A free email subject line generator for sales, transactional, and marketing emails. Outputs 10 variants per topic, each using a different conversion pattern (specificity, curiosity, urgency, personalization, social proof).
Type your email topic + pick the audience (cold outreach / newsletter / transactional / sales follow-up / re-engagement). The generator outputs 10 subject line variants under 50 characters AND a matching preview text for each.
Your email
10 subject lines
our new BYOK AI pricing?
A quick question — should take 30 seconds to answer.
3 ways our new byok ai pricing
Inside: the three I'd actually use myself, ranked.
[First name], our new byok ai pricing
Saw this and thought of you — fast read.
What nobody tells you about our new byok ai pricin
The one thing I wish I'd known earlier.
our new BYOK AI pricing (today only)
Sending early so you can act before EOD.
Stop doing our new byok ai pricing
What to do instead — 2-minute read.
How [Person] does our new byok ai pricing
The exact playbook, broken down step-by-step.
Last chance: our new byok ai pricing
Closing this in 24 hours — figured I'd give you the heads-up.
Re: our new byok ai pricing
One ask — and an idea you might find useful in return.
our new BYOK AI pricing?
Reply yes or no — I won't follow up either way.
Who this is for
Marketers, founders, and creators sending email — newsletters, cold outreach, sales follow-ups — who want subject lines under 50 chars without writing them from scratch.
The problem this solves
Inbox preview is ~50 characters on most mobile clients. Most generators output 70-90 char subject lines that get truncated. The generator enforces ≤50 chars AND outputs preview text (the next-line teaser) so the inbox preview is intentional, not accidental.
Sales email subject lines under 40 characters get approximately 18% higher open rates than subject lines over 60 characters — yet 53% of B2B sales reps ship subject lines over 50 characters.
Source: HubSpot Email Marketing Benchmarks 2024 + Outreach.io Subject Line Performance Study 2024
How to use it
- 01
Type the email topic
One sentence. What's the email about? The clearer the topic, the more variant patterns the generator can pull from.
- 02
Pick audience type
Cold outreach / newsletter / transactional / sales follow-up / re-engagement. Each audience weights different patterns (urgency for cold, curiosity for newsletter, etc.).
- 03
Get 10 subject line variants
All ≤50 chars. Each uses a different pattern: question, number, [first-name], curiosity-gap, urgency, contrarian, social proof, FOMO, direct ask, [reply-yes-no].
- 04
Pick + use preview text
Each variant comes with a matching ~70-char preview text. The combo is what shows in mobile preview — designed together, not separately.
What you get
- ✓ 10 subject line variants per email (all ≤50 chars)
- ✓ Matching preview text per variant (~70 chars)
- ✓ 10 distinct patterns (question, number, name, curiosity, urgency, etc.)
- ✓ Audience-tuned weighting (cold ≠ newsletter ≠ sales)
Frequently asked
What's the difference between this and the newsletter subject line tester?
This generator creates new subject lines. The tester scores subject lines you've already written. Use them together: generate, then test the best 2-3.
Should my email subject line match my preview text?
Match the topic but don't repeat the exact phrase. Preview text should expand on the subject, not duplicate it.
Are emojis effective in B2B emails?
Generally no. B2B inboxes treat emoji subject lines as promotional. Reserve for B2C/creator audiences.
Should I personalize the subject line?
Yes when you have the data. "{{first_name}}, quick question" outperforms generic by 15-25%. But avoid over-personalization ("Adam, I noticed you visited our site at 2:17am") which feels stalky.
What words trigger spam filters in 2026?
"Free", "guaranteed", "act now", "limited", excessive punctuation, ALL CAPS. Modern filters also catch "click here", "make money", "free trial."
Related tools
Author + maintainer
Adrian Berisha — Founder of Clipflow. Indie SaaS builder shipping creator tools full-time since 2024. All tools and benchmarks on this page are reviewed quarterly. Last review: May 2026.
@clipflow on X · LinkedIn · hi@clipflow.to
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