How to use Klaviyo’s subject line assistant

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You will learn 

Learn how to use Klaviyo’s AI-powered subject line assistant to improve your subject lines and streamline your campaign sending process. Choose an auto-generated subject line that’s customized based on your brand and campaign goals, or use these subject lines as inspiration when you draft your own. 

Generate a subject line 

  1. Navigate to the Campaigns tab
  2. Click Create Campaign
  3. Choose Email
  4. Name your campaign, choose the lists or segments to send to, and click Continue to Content
  5. Click the lightbulb icon to open the subject line assistant
    A user opens Klaviyo's subject line assistant
  6. Choose a campaign type from the options below: 
    • Promotion
      Select if you’re announcing a sale, exclusive gift, or other promotional offering 
    • Announcement
      Select for product launches or other major announcements 
    • Newsletter
      Select if your message is intended to educate recipients or share information about your business 
    • Other
      If your message doesn’t fit into any of the above categories, choose this option
  7. Choose a message type that best fits your campaign
  8. Complete the open-text fields that follow, then click Generate
  9. Select a generated subject line by clicking it, or click Generate again to see a new batch of suggestions 
    • Note that you can make edits to the generated subject line after selecting it 

Tips for success

The Description field works best with natural language (i.e., whole sentences). If you’re not sure what to write, consider copying the product or event description from your website, or write as if you’re describing the topic to a friend. Here are some sample descriptions for a product launch: 

  • The ultra cushioned, ultra comfortable, ultra versatile trail running shoe
  • We created the trail running shoe of your dreams, so you can spend less time shopping and more time outside

The Klaviyo subject line generator shows four AI-generated subject lines

You can click Generate as many times as you want, until you find a subject line you like. Consider making changes to the Description field for more varied results, or use a generated subject line in the Description field for others like it. 

Analyze your results and learn more 

Use the Analyze tab to see your best-performing recent subject lines and better understand what works for your audience. This tab displays the best-performing subject lines (based on open rates) from the last 90 days for campaigns that were sent to a similar number of recipients. 

Visit the Learn tab for tips on drafting subject lines, including sample subject lines that reflect best practices. Click Refresh under any suggestion for more examples. 


After completing these steps, you’ll have access to unlimited subject line ideas to use in your next campaign. To better understand which subject lines resonate with your audience, consider A/B testing a few options

Additional resources 

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