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Email campaign best practices

How you compose and style your email campaign depends on your brand and goals. This guide offers general tips and best practices to help you send successful campaigns, no matter how you define success.

Subject line and preview text

Your subject line and preview text are your first impression, and can inspire someone to open and read your email. Ensure this text is evocative and compelling. Think about the benefit to the reader: What would make it worth their time to click through and read your campaigns?

Experiment with different types of subject lines and review your analytics to see which ones work for your audience. Here are some ideas:

  • Be specific. "We're opening a store in SoHo!" is better than "Big news!"
  • Promote sales or discounts.
  • Be clear and concise. Short, focused text helps readers understand your message.
  • Ask a question to encourage readers to open the email to find out more.
  • Use emojis to help your email stand out in a full inbox.
  • Ensure your text is accurate. This maintains your subscribers' trust, and may help you meet legal requirements like CAN-SPAM, CASL, and PECR

Email content

As you compose your campaign, we recommend:

  • Keep it short and focused on one topic.
  • Include one clear call to action, such as a link to your site or a product they can buy. Ask yourself: What's the one thing I want everyone reading this campaign to do?
  • Be consistent with your branding. Use the same language and tone you use on your website.
  • Include a link to your site, such as a text link or a button. Site logos link to your site automatically.


Keeping your style simple helps your readers focus on your content and message. Here are some suggestions:

  • Use pops of color to draw attention to your call-to-action, like a brightly colored button.
  • A light background color with dark text is generally easiest to read.

We have several guides about style and design. Although they're focused on website design, most of the tips apply to email campaigns too:


Images can be a great way to set the tone and intrigue readers. When adding images, follow these guidelines:

  • Your image name becomes its alt text, so ensure the file name briefly describes the image. See our tips for alt text.
  • Use .jpg, .gif, or .png format only.
  • Only use letters, numbers, underscores, and hyphens in file name
  • We recommend using image files of less than 500 KB for best results, though the limit for an individual image upload is 20 MB.
  • Include text to help get the message across. Some email providers may hide images, so add text in your campaign that will convey your message even if the image is missing.
  • There's an image resolution limit of 120 MP (megapixels).
  • If a section has multiple images, we recommend using images with the same dimensions.  
Tip: Email Campaigns' built-in responsive design resizes your images based on the visitor's screen.

Mailing lists

It can be tempting to add as many users to your list as possible, but you'll get the best results from people who signed up voluntarily and are excited to engage with your content. Adding people without their permission can annoy them, cause filters to mark you as spam, and may violate legal restrictions like CAN-SPAM, CASL, or PECR.

A healthy mailing list has low unsubscribe rates and doesn't include invalid, incorrectly formatted, or fake addresses. To keep your mailing list as healthy as possible, follow these tips:

  • Add areas on your site where people can sign up for your newsletters.
  • Never use a mailing list that you purchased or was given to you, because those subscribers haven't said they want to receive your email.
  • If you require your users to provide an email address before seeing or downloading content, it can cause them to use fake email addresses.
  • When exporting a mailing list from another service provider, like Mailchimp, ensure it only includes active, engaged subscribers. Before importing into Email Campaigns, remove any unsubscribed email addresses (including "culled" or "cleaned" addresses) from the list.
  • If you've had your list for a long time, it may have a number of old or disused email addresses. Consider sending an email inviting your users to resubscribe to a new list, and then delete the old one. This ensures that users who are no longer interested in your content don't receive it.
  • Periodically go through your mailing list and delete any emails that are obviously fake, invalid, or duplicates. Even when you’re following best practices, you might get invalid signups from spambots, people making mistakes, and people trying to send you inappropriate or unsolicited information.
  • If you have a large list that isn't performing well, consider using a list cleaning service such as BriteVerify or ZeroBounce.
Note: Troubleshooting the contents of a mailing list is outside the scope of Squarespace support. If you see an "Upload Failed" message, review the bullet points above and edit your list to ensure it’s healthy. Remember, you shouldn’t send campaigns to anyone who hasn’t consented to receive emails from you.

Unsubscribe link

Ensure the Unsubscribe option is visible and easy to use.

Allowing people to unsubscribe is required, but it's also smart. People unsubscribe for a variety of reasons, and not necessarily because they don't enjoy the content. For example, they may already get your newsletter at a different address, or may be taking a break from all newsletters for a while. If you let them unsubscribe easily, they're more likely to resubscribe in the future.

Additionally, if the unsubscribe link is difficult to see, people may report you as spam as a method of unsubscribing, which could increase the likelihood that future campaigns to other subscribers will be marked as spam.

Tip: To learn more, visit Email campaign unsubscribes.

Legal address

Ensure the business name and address that displays in the footer is a valid physical postal address. This is required by anti-spam and privacy laws such as CAN-SPAM. It also helps build credibility with customers, and can help your campaign avoid spam filters.

For more information, including what to do if you don't have a business name or business address yet, visit Adding your business name and address.

Avoid spam filters

If an email goes into a spam folder or bounces altogether, the reader will never see it. Here are our top tips for getting your campaign into their Inbox:

  • Verify your email.
  • Use a custom email address and verify its domain.
  • Only include people who've confirmed they want to receive your campaigns.

To learn more, visit Avoiding spam filters.

Know your legal requirements

Review any anti-spam and privacy laws for your country and the country of anyone you're sending campaigns to, such as CAN-SPAM, CASL, or PECR. Violating these laws can result in fees and other penalties.

More tips

  • Think about other emails your subscribers are getting from you, such as commerce notifications. Keep your tone and branding consistent across all these messages.
  • After sending a campaign, review how it performed and compare that to previous campaigns. Over time you'll learn what works best for your audience.
  • Always send a test email before sending your campaign. If possible, mail the test to multiple people to get their perspectives.
  • Consider crafting an A/B test to see what content works best for your subscribers.
  • Experiment with the timing of when you send your campaigns. For example, do your subscribers check email first thing in the morning? In the evening before bed? Do they behave differently with emails sent on weekdays vs. weekends? Follow your analytics on each campaign to see what works best.
  • Use mail merge tags to add personalized content for each subscriber, like their name. Personalizing your campaigns makes them feel less generic and may lead to a higher opened rate.
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