Email providers have automatic systems that filter out unsolicited emails sent in bulk, also known as "spam." Emails flagged as spam are typically filtered into a separate folder. They might also "bounce," which is when they're rejected and not delivered at all. Either way, they may never be seen by the recipient.

Spam filters vary from provider to provider, and whether an email is flagged depends on many factors. There isn't a way to guarantee your email campaigns won't be marked as spam, but following the suggestions in this guide can help minimize how often this happens. This guide also explains the industry best practices that are built into every Email Campaign.

Note: Marketing strategy falls outside of the scope of Squarespace support. Because email providers use complex algorithms for their filters, and because everyone's marketing needs are unique, we're unable to provide specific advice to customers.

Use a custom email

Spam filters are more likely to reject emails sent from free email providers, such as Gmail and Yahoo. For example, susiesmith@gmail.com would be more likely to bounce than susie@susiesmith.com.

A custom email is associated with a custom domain. To create the email address susie@susiesmith.com, you'd need to register the domain www.susiesmith.com.

• If you don't have a custom domain for your site, you can register one through Squarespace.
• If you have a domain, but don't have a custom email address, you can set one up with Google Workspace.

Tip: After you've set up your email and added it to your sender details, it's important to verify its domain.

Note: If you recently purchased your domain, we recommend sending your first few campaigns to a smaller mailing list—for example, 200 contacts or fewer. Emailing a large number of contacts from a brand-new domain can trigger spam filters.

Verify your email's domain

An email's domain is everything that comes after the @ symbol. If you're sending campaigns from a custom email, verifying its domain shows spam filters that your email is valid and you have access to it.

Squarespace domains are verified automatically. If you bought a domain from a different provider, you can:

• Transfer the domain to Squarespace so it verifies automatically in Email Campaigns.
• Manually add verification records to your third-party domain’s DNS settings.

Note: Verifying a domain isn't an option for free email providers like Gmail or Outlook.

Verify your email

Whether you use a custom email or a free email (such as Gmail or Outlook), we recommend verifying it. This tells us your email address is valid and you have access to it. Spam filters usually block emails that seem to come from invalid addresses.

To verify your email, go to your Email Campaigns dashboard, click Settings, click Sender Details, then click Verify Email. From there,  you'll copy a code from an email we send to your address. For detailed steps, visit Setting up sender details.

Only use emails with permission

Ensure you have permission to send email campaigns to every subscriber on your list. People who signed up voluntarily and are excited to receive your content are less likely to mark your campaigns as spam.

A great way to ensure this is to encourage subscribers to sign up for your mailing list themselves, by adding a newsletter subscribe forms to your site or checkout page. For more help, see our list of subscription options.

Note: Never purchase mailing lists, and don’t use a list if you don’t know where it came from. Spam filters can detect when people use purchased or scraped email addresses, and are likely to flag you as suspicious.

Suggest people add you to their contacts

Encourage people to add your email address to their contacts. This is a great option for people who contact you to say that your campaigns went into spam. If the spam filter sees that you're on your recipient's contact list, it means that they want to receive campaigns from you.

Include a legal name and address

Ensure the address you add to your footer is valid and that you're able to receive mail there. Some spam filters look for this information to help confirm you're not spam.

For answers to frequently asked questions, visit Adding your business name and address.

Don't ask for payment information

Don't use email campaigns to ask for credit card numbers, bank account numbers, or other sensitive data. These requests can cause inboxes to flag your email as spam. If you need to collect a payment, link to a secure payment form instead, like a donation block.

Craft your content wisely

Keep your content relevant, accurate, and on-brand. Email providers may flag overly pushy promotional copy.

Review your analytics and, if possible, do A/B tests to see what content resonates with your subscribers. For more tips, visit our best practices.

Think about your subscribers

In addition to the content spam filters look for, subscribers can mark emails as spam manually. If enough people mark your campaigns as spam, it can cause spam filters to block your campaigns in the future.

There aren't firm rules for exactly what content you should or shouldn't use, but think about your brand and your subscribers. Avoid sending content that could be perceived as irritating or abusive.

Paste plain text

Stray code can trigger spam filters. When copying and pasting text into your campaign, we recommend using keyboard shortcuts to paste as plain text. This strips all stray formatting code that can carry over from an external program.

About Email Campaigns and spam

Squarespace Email Campaigns are set up for success. Every email campaign you send includes industry best practices such as:

• Unsubscribe links and list-unsubscribe header code
• DomainKeys Identified Mail (DKIM) signing
• Sender Policy Framework (SPF) validation protocol.
• MIME Multipart formatting for HTML and plain text
• Automatic hard bounce handling

How will I know if my campaign is sent to spam?

There isn't a foolproof way to see how many of your campaigns were automatically filtered into spam folders or blocked altogether, but reviewing your unsubscribed and open rates can help you get a sense of your campaign's success. For more help, visit Tracking email campaign analytics.