Tool

AI subject line generator:
Create high-converting email headlines

After sending 40 billion emails for leading brands, we know what drives engagement. Our AI subject line generator makes it easy to put those insights into your own campaigns.

After sending 40 billion emails for leading brands, we know what drives engagement.
Our AI subject line generator makes it easy to put those insights into your own campaigns.

How to use the AI subject line generator

How to use

Define your goal: Are you looking for a "curiosity gap" or a direct "benefit-driven" headline?
Know your audience: Define the tone to improve AI output: professional, witty, or urgent.
Test and iterate: Use the generator to create five variations, run an A/B test in your ESP, and plug the results into our A/B testing calculator to see what resonates with your segment.

Define your goal: Are you looking for a "curiosity gap" or a "benefit-driven" headline?
Know your audience: Define the tone: professional, witty, or urgent.
Test and iterate: Create five variations, run an A/B test in your ESP, and plug the results into our A/B testing calculator.

Check out our ultimate guide to A/B testing.

What is this email about?

And/or

Your idea for a subject line:

Use emojis:

Use cases for AI-generated subject lines

B2B sales & cold outreach

Cold emailing is a volume game, but the subject line must feel personal. Use the generator to create "pattern interrupt" headlines that don't look like typical sales pitches. Example: "Quick question regarding [Company Name]'s Q4 strategy."

E-commerce & retail

For retail, urgency and value are king. The AI can help you find fresh ways to announce a sale without sounding like every other brand in the "Promotions" tab. Example: "Your cart is lonely (and 15% off for the next 2 hours)."

Content newsletters

If you’re a thought leader or a publisher, your subject line needs to promise value. The AI focuses on "how-to" and "listicle" formats that have historically high open rates. Example: "5 ways to automate your email workflow by Friday."

FAQ

What is an AI subject line generator?

An AI subject line generator is a tool that uses machine learning (like GPT-4 or proprietary models) to generate catchy, relevant, and high-performing email headlines based on a short description of your email content.

What is the ideal length for a subject line?

For mobile optimization, we recommend keeping subject lines between 40 and 60 characters. Since over 60% of emails are opened on mobile devices, our AI subject line generator prioritizes brevity to ensure your message isn't cut off.

Will AI-generated subject lines trigger spam filters?

Our tool is designed to avoid "spammy" language (like "FREE $$$ NOW"). However, it is always best practice to avoid excessive capitalization or multiple exclamation points to ensure high deliverability.

Why are email subject lines so important?

Your subject line determines whether your email gets opened, ignored, or sent to spam. If it triggers spam filters or feels misleading, your message may never reach the inbox.

Should I use emojis in my subject lines?

Yes, in moderation!✨Emojis can increase open rates by helping your email stand out visually. Our generator can suggest relevant emojis based on the sentiment of your copy.

How do I improve my email open rates?

Beyond using a great subject line, you should optimize your preheader text, maintain a clean email list to avoid spam filters, and ensure your "from" name is recognizable. High-quality responsive email design also plays a major role in keeping subscribers engaged over time.

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