Using the AI subject line and preheader generator
Writing a subject line after you have just finished building an entire email can quickly feel like an afterthought. The AI subject line and preheader generator helps you get past that blank-screen moment by suggesting combinations based on a description of your email content. You choose from the suggestions, adjust them where needed, and add them to your campaign in one click.
This feature is available without limits on all subscription plans.
How do you use the generator?
Step 1: Open the generator
The generator is accessible from the first step of the campaign wizard, where you set your subject line and preheader.
- Start creating a campaign and go to step 1.
- Find the subject line field.
- Click the Suggest button next to the subject line field. This opens the generator in a popup.
Step 2: Describe your email
The generator needs context to generate useful suggestions. In the description field, write a short summary of your email. The more specific you are, the better the suggestions will be.
A good description covers three things:
- The main message of the email. What is it about?
- The call to action. What do you want the reader to do?
- Your audience. Who are you sending this to?
Example: "We are launching a new line of running shoes for women. The email highlights the lightweight design and includes a 15% launch discount. Audience: existing female customers who bought running gear before."
Step 3: Choose a tone and a purpose
Select a tone and a purpose from the two dropdown lists. These guide the style and the intent of the suggestions.
Available tones are: formal, informal, friendly, humorous, inspirational, motivational, urgent, informative, promotional, persuasive, conversational, narrative, mysterious, and thought-provoking.
Available purposes are: promotional, informative, transactional, educational, engaging, relationship-oriented, retention, lead nurturing, event promotion, product launch, customer support, community-building, onboarding, and seasonal or holiday-themed.
Support tip Match the tone to your brand voice, not just the campaign type. If your brand is always conversational, choose conversational even for a promotional campaign. Contacts notice inconsistency.
Step 4: Generate suggestions
Click Generate. The generator produces six suggestion cards. Each card shows a preview of the sender name, a subject line, and a preheader, so you can see exactly how the combination looks in an inbox.
Step 5: Review and select
You have several ways to work with the suggestions:
- Select a full card. This chooses both the subject line and the preheader from that card at the same time.
- Regenerate. If none of the suggestions work, click Regenerate for a completely new set.
Step 6: Apply to your campaign
When you are happy with your selection, click Use these. The fields for the subject line and preheader in your campaign wizard are filled in automatically. You can still edit them manually before sending.
Getting better suggestions
The quality of the suggestions depends heavily on the quality of your description. A vague description produces generic results.
| Vague description (weaker results) | Specific description (stronger results) |
|---|---|
| We have a sale. | 25% discount on all jackets this weekend. CTA: shop the sale. Audience: customers who viewed outdoor clothing in the last 30 days. |
| Monthly newsletter. | Monthly product update newsletter. Highlights: new integration with Zapier, improved reporting dashboard. Audience: existing Pro plan customers. |
| Event invitation. | Invitation to a free online webinar on strategies to grow your email list. Date: next Thursday at 11:00. CTA: register now. Audience: small business owners who are new to email marketing. |
Common mistakes
- Using suggestions without reviewing them. The generator provides starting points, not final text. Always read the suggestions carefully and adapt them so they match your exact offer and tone.
- Regenerating repeatedly without changing the description. If the first set of suggestions is not right, the problem is usually the description. Refine it first before generating again.
- Ignoring the preheader suggestions. The generator creates subject line and preheader pairs that are designed to work together. Combining a generated subject line with a hastily written preheader misses part of the value.
- Treating AI output as final. Subject lines with specific numbers, deadlines, or personalisation that you add yourself often perform better than a purely generated suggestion. Use the generator to get unstuck, and then make it your own.
Next steps
- See "What makes a good subject line?" for an explanation of what makes a subject line good, which helps you evaluate and improve the suggestions from the generator.
- See "Writing a preheader" if you want to write or edit a preheader manually.
- Set up AB testing to compare a generated subject line with a version you wrote yourself. Over time you will see how much value the generator adds for your specific audience.