Shopify Email Subject Line Generator: Using Sidekick
Shopify’s built-in email subject line generator is Sidekick, inside Shopify Messaging: when you create a campaign, an icon in the Subject field turns a short prompt into a subject line, and the same icon in a text section drafts the body. It works in every language Shopify supports, in the language of your prompt. What you put in the prompt decides how useful the line is, and you still check every suggestion, because Shopify holds you responsible for what you publish.
The steps and prompt advice come from Shopify’s Help Center page on generating email subject lines and body text, and the subject-line rules from writing best practices, both read on October 23, 2026. The current Help Center page describes it under Sidekick and in all supported languages.
Generate a subject line step by step
- In the admin, go to Apps > Messaging.
- Click Create campaign and select a template.
- In the Subject field, click the Sidekick icon.
- Enter a prompt describing the email you’re sending and submit it. The generated line goes straight into the field.
- Edit it to match your brand, then click Save.
If you’ve already typed a draft subject line, Sidekick picks keywords from it automatically. For body text, click the same icon in the rich text editor of a text section.
Prompts that give better lines
Shopify names four kinds of input that improve the result:
| Input | What to include | Example |
|---|---|---|
| Campaign type | What the email is for | product restock, spring sale, birthday discount |
| Product keywords | Product name and type, plus what makes it worth buying | “Monaco” alone is vague; “New arrivals, Monaco linen shirt, 10% off” isn’t |
| Brand terms | Words you want kept as written | a product nickname or tagline, such as “mint-astic” for a mint lip balm |
| Other details | Anything the reader needs | the sale amount and which products are included |
Shopify notes that the generated text rephrases what you give it but usually keeps special words such as brand names. Six prompts of our own, built from those inputs:
- “Restock email: our Monaco linen shirt is back in all sizes, limited batch, friendly tone, under 6 words.”
- “Spring sale, 20% off all outdoor cushions until Sunday, for existing customers, plain and direct.”
- “Birthday discount email, 15% off for one week, warm but short, include the word gift.”
- “New arrivals: three coffee blends from Ethiopia, Colombia and Brazil, for subscribers who bought beans before.”
- “Last day of free shipping on orders over $50, urgent but not pushy, no exclamation marks.”
- “Care guide for leather bags, no discount, practical, curiosity-driven.”
Each one states the campaign, the product, the offer (or that there is none), the audience where it matters and a tone. Without them, Sidekick has little to work with. If a suggestion is close but not right, edit it yourself or generate again with a more specific prompt.
Check every line against these rules
Shopify’s guidance for subject lines and preview text applies to generated lines as much as written ones:
- Keep the subject line to 3 to 6 words or under 50 characters, so it reads on a phone.
- Make it relevant to what’s inside, and write it last so it matches the content.
- Always add preview text that complements the subject instead of repeating it. Shopify’s example pairs “Check out our new spring gear” with “Don’t miss out on 10% off shorts, tanks, and more for the warm weather ahead.”
- Avoid all capitals and excessive exclamation marks.
Then check the facts. Shopify’s caution is that you’re responsible for the accuracy of generated content and should read it closely before publishing. Check every generated line against the actual offer, and remove any discount, deadline or free shipping the campaign doesn’t include.
Measure the result in the campaign report afterward: opens and clicks per campaign, with open rates read as estimates. Our guide to email writing best practices covers the rest of the email.
Body text too
The same Sidekick icon in a text section drafts body copy from a prompt, using the same four inputs. Shopify’s rules for the body: under 200 words or about 20 lines, the important part within the first two scrolls on mobile, and the offer in text rather than only in an image. For recovery emails specifically, see abandoned cart email examples. The email and popups hub has the rest of our email guides.
FAQ
Is the Shopify subject line generator free? It’s part of Sidekick in Shopify Messaging, and Shopify’s page doesn’t mention a separate charge for generating text. Sending the email is billed under Messaging’s usual email pricing.
Does the subject line generator work in my language? Email text generation works in all languages Shopify supports. Write the prompt in the language you want the subject line in, and the result matches it.
Is it Shopify Magic or Sidekick? Shopify’s current Help Center describes the feature under Sidekick. Older pages and articles that call it Shopify Magic and limit it to English are out of date.
Can Sidekick write the whole email? Sidekick drafts the subject line and the body text of text sections. You still choose the template, products and discount, and review everything before sending.