Squarespace does a lot of things well. Transactional form email is not one of them. Form-submission notifications, contact-form replies, and newsletter-signup confirmations all leave the platform from a shared sender controlled by Squarespace, with Squarespace's DKIM. That setup is fine in the early days of a new site but starts showing cracks once you cross a couple of hundred form submissions a day.
Squarespace's default sender works, but placement varies a lot by mailbox provider. Gmail is forgiving; Outlook and Yahoo are not. For high-volume forms, forward notifications to Google Workspace or route them through Zapier + a dedicated SMTP provider. Always seed-test before assuming it works.
How Squarespace sends form email
When someone submits a contact form, newsletter signup, or order form on a Squarespace site, the platform generates an email internally and hands it to the shared mailer. The From header is usually set to the email you configured in the form block (say, hello@yourstudio.com), but the actual envelope sender and DKIM selector belong to Squarespace:
From: Your Studio <hello@yourstudio.com>
Reply-To: form-submitter@gmail.com
Return-Path: bounces+xxx@mailer.squarespace.com
DKIM-Signature: d=mailer.squarespace.com; s=sq202301; ...
Received: from mailer.squarespace.com ...This is a shared-sender pattern. It has two consequences for deliverability:
- DKIM aligns to
squarespace.com, not to your domain. If you publish a DMARC policy ofp=rejectonyourstudio.com, Squarespace form emails will be rejected at strict-DMARC mailboxes because the DKIM alignment fails. - You inherit the reputation of a shared pool. If another Squarespace user sends spammy newsletters, your notifications can be briefly affected. In practice, Squarespace manages the pool well, but the signal is not perfect.
Our seed-test results
We submitted 100 forms on fresh Squarespace sites and routed the notifications to our seed-mailbox grid. Aggregated inbox placement:
MAILBOX PROVIDER INBOX OTHER/SPAM
Gmail 89% 11% (mostly Updates/Promotions)
Outlook.com 72% 28% (Junk)
Yahoo Mail 78% 22%
iCloud 84% 16%
ProtonMail 91% 9%
Mail.ru 68% 32%
Yandex 74% 26%Solid at Gmail and ProtonMail, weak at Outlook and Mail.ru. High-volume forms (200+ submissions/day) see worse Outlook numbers — one studio we tested had notifications land in Junk 45 percent of the time until they switched to Google Workspace integration.
Option 1: Google Workspace integration
Squarespace has a native connector for Google Workspace. When enabled, form notifications are sent through your Workspace account rather than the shared Squarespace mailer. The From header, envelope sender, and DKIM all line up on your domain.
Pros:
- DKIM signs with
yourstudio.com. SPF and DMARC alignment work cleanly. - Form notifications go into the Sent folder of your Workspace mailbox — audit trail for free.
- Higher per-day quota (2,000/day on standard Workspace vs shared limits on Squarespace).
Cons:
- Requires a paid Workspace seat.
- Setup involves OAuth and can break if the granting admin leaves the organisation.
Squarespace Email Campaigns is a separate product from form notifications and has its own reputation pool. For genuine newsletter content, route through Mailchimp, Brevo, or Beehiiv with your own domain authenticated — do not rely on Squarespace's bundled mailer for marketing volume.
Option 2: Zapier + dedicated SMTP
For users who want notifications under their own domain but do not have Workspace, the Zapier route works well.
- In the form block, set the notification email to a custom address like
forms@yourstudio.com. - Connect that mailbox (or a forwarder) to Zapier as a trigger.
- In the Zap, call a Send Email step via Postmark, SendGrid, or Mailgun — all of which can authenticate as your own domain with DKIM.
- Forward the form payload to whatever recipient (you, your team, a CRM) you actually want.
Added benefit: Zapier logs every form submission, so nothing gets lost even if downstream email fails.
Seed-test your own Squarespace forms
Generic data is useful; data from your own site is more useful. Run through this quick diagnostic:
- Identify every form block on the site. Squarespace surfaces them in Form & Lightbox Storage under each page.
- Submit each form once with a seed-mailbox address like the one our free inbox checker provides — you get a single address that fans out to 20+ real mailboxes.
- Review the placement per provider. Pay extra attention to Outlook and Mail.ru.
- Inspect the message source in Gmail. Look at
Authentication-Results. You want to see whether DKIM signs withsquarespace.comor with your own domain (tells you whether the Workspace integration is actually active).
Gotchas we see often
- Strict DMARC breaks Squarespace forms. If you set
p=rejectfor the From domain without authorising Squarespace in SPF or switching to Workspace, Outlook will start rejecting form emails outright. Either loosen DMARC top=noneor fix the alignment. - Reply-To confusion. The Reply-To header is set to the form submitter's address. Replies from your team go to the submitter, not back through Squarespace — which is usually what you want, but occasionally surprising.
- Spam-word triggers in template copy. Squarespace's default notification template is simple, but adding "Free quote inside!" in the subject tanks placement. Keep subjects factual.
A native Squarespace integration is in private beta. It plugs into the form submission event, seed-tests the notification across 20+ mailbox providers, and tells you if placement drops after a Squarespace template update.
Frequently asked questions
Can I change the From address on Squarespace form notifications?
Yes, in each form block's Storage tab. That sets the From header — but the DKIM signer stays Squarespace unless you enable the Google Workspace integration.
Why do some of my form emails never arrive?
Most likely Outlook or Mail.ru quarantine. Check the recipient's Junk folder. If you have a strict DMARC policy, some strict receivers reject outright — look at the DMARC aggregate reports to confirm.
Does Squarespace support custom DKIM for forms?
Not directly for form notifications. The Email Campaigns product does allow authenticated domains, but form emails are signed by Squarespace. Use the Workspace integration or a Zap-based relay if custom DKIM is required.
How often should I re-test form placement?
Monthly is a good baseline. After any significant Squarespace template update, or if you change DNS (SPF/DMARC), re-run the full test immediately.