Use AI to Generate Subject Lines

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Amanda Payne avatar
Written by Amanda Payne
Updated over a week ago

We all know good subject lines are vital to email open rates. We also know there's a knack to writing strong subject lines.

Some of you are gifted copywriters. I admire you (and secretly hate you, too). You bang out great subject lines, lickety-split. Other folks, like me, need time, multiple edits, and a little help.

That's why I'm so excited about our AI tool called tinyEinstein. You input basic information, and the AI generates multiple subject line suggestions, lickety-split.

Here's how.

Accessing the AI

You can access the tinyEinstein tool when creating a new campaign or editing an existing draft campaign (which has not been sent out yet).

New campaign

Click Campaign on the side menu and then click the Create campaign button. Click Email campaign in the pop-up window. The Details page displays. You can enter a campaign name now (that's optional) or later.

Click Try now to open tinyEinstein.

Draft campaign

You can also use tinyEinsten with a draft campaign. Here's how.

Click Campaign on the side menu and then click the name of a draft campaign. At the top of the next page, click the Details and then Edit on the next page. On the Details page, scroll down to tinyEinstein and click Try now.

Entering inputs

After you click Try now (for a new or draft campaign), the Email Subject Lines page displays. This is where you feed inputs into the AI machine, so to speak.


Enter a company or product name into this optional field. Maximum 150 characters.

Tone of Voice

Next, you can influence the tone (e.g. emotion created through word choice) that the AI injects into the subject line. Click the field and select an option. (required)

Merge Tags

You can inject a tag into the subject line. This is an optional field, and I encourage you to use this field sparingly. Tags gobble up character space in the subject line (subject lines have a 150-character limit). If you add too many tags, the subject line will be truncated.

  • Best practice Limit the number of merge tags in the subject line to a maximum of two.

Click the Merge Tags field and select an option:

  • first name

  • last name

  • birthday

  • company


This mandatory field is where you enter the secret sauce that helps our AI whip up compelling subject lines.

Enter up to 300 characters. Generally speaking, the more details you include, the better range of the subject line suggestions you get.

  • White hat tip If you're stuck for word ideas, Google your company/product name. Amazon and Walmart are also good places to find rich descriptions if you're promoting a product.

Generate results

Click the button, and the AI generates three subject line suggestions. Each suggestion builds on the selected tone and pulls in the name and tag (if selected) plus text from the description.

At this point, you have four options.

  1. Select one suggestion and click Use. This takes you to the next step, where you build the campaign. You can also edit the subject line (if you want).

  2. Go back to the Inputs page, make changes, and generate a new set of results.

  3. Use a subject line that you previously saved as a Favorite.

  4. Scroll through the History log and use a subject line that you generated in the past.


  • Click the Favorites tab to see your saved subject lines. To save a line as a Favorite, simply click the star icon next to a subject line. All your favorites have a yellow star.


  • Click the History tab to see every subject line you've generated with tinyEinstein. Use the search bar to narrow down the list of options.

Regenerate results

In this example, I want to generate new results with a different tone. I change the tone from Uplifting to Friendly and keep one Merge Tag.

Notice (in the below screenshot) that the results count changes. In this example, my results count changes from 3 to 9. That's because I clicked the Generate results button two times.

  • Note Each time you generate results, the AI produces three suggestions. Each suggestion counts against your daily limit.

What's my daily limit?

Each tinyEmail plan comes with a different daily limit. Sorry, it's not possible to generate hundreds of suggestions each day.

To see your daily limit, click the info icon. The pop-up window shows your account plan, the number of subject line suggestions you can generate each day, and the current number generated.

  • FYI tinyEinstein is available with your free or paid plan. The screenshot below shows the daily limits (number of AI-generated results per day) for each plan.

Next steps

Once you find a great subject line, click the Use link. tinyEmail automatically loads the AI-generated subject line into the field. From here, you can continue to create or edit your campaign.

After you complete a campaign and reach the Schedule stage, tinyEmail inserts a reminder. Each campaign with an AI-generated subject line has a tinyEinstein tag.

That's it!

Now you're sending campaigns with tinyEinstein.

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