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This guide walks you through adding the required DNS records for Lettr using Squarespace’s DNS management. Squarespace is a website builder and hosting platform that also offers DNS hosting for domains managed through its Squarespace Domains panel. You will configure a sending domain (CNAME, DKIM TXT, and DMARC TXT records) and, optionally, an inbound domain (MX records), tracking domain (two CNAME records), and storage domain (CNAME and two TXT records).

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Sending Domain Setup

A sending domain authenticates your outgoing emails with DKIM and DMARC, ensuring they are delivered reliably and not marked as spam. This requires a CNAME record for domain verification, a TXT record for DKIM signing, and a TXT record for DMARC policy. To create a sending domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Sending Domains
  3. Click Create Sending Domain
  4. Enter your desired sending subdomain (e.g. mailing.company.com)
  5. Click Create Domain
Use a subdomain (e.g. mailing.company.com) instead of the root domain (company.com). A subdomain provides proper reputation segmentation and is required if you also plan to receive emails with Lettr.
Click your new domain in the Sending Domains list. This will display a list of DNS records that need to be configured. Keep this page open — you will need these values soon.

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Configure Squarespace DNS

Log in to your Squarespace account, click the domain you want to configure, then click DNS in the side panel, followed by DNS Settings.
Squarespace only allows custom DNS records for domains purchased or managed through Squarespace. If your domain is registered elsewhere, you may need to transfer it to Squarespace or update your nameservers before adding records.
If your domain was purchased through Squarespace or your nameservers already point to Squarespace, skip nameserver configuration entirely. Your domain is already using Squarespace’s nameservers by default — proceed directly to adding the DNS records below.
If you registered your domain elsewhere but want to manage DNS on Squarespace, you must first transfer the domain to Squarespace or update the nameservers at your registrar to Squarespace’s nameservers (ns1.squarespace-dns.com and ns2.squarespace-dns.com).
Until the nameservers are updated, any records you add in Squarespace will not resolve.

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Add CNAME Record

The CNAME record verifies domain ownership with Lettr’s email infrastructure. Copy the CNAME values from Lettr to Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to CNAME.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix). For example, paste only mailing.
  4. Copy the Value from Lettr and paste it into the Alias Data field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. mailing, not mailing.company.com).

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Add TXT Record (DKIM)

The DKIM record adds a cryptographic signature to your outgoing emails, allowing recipients to verify they were sent by an authorized sender. Copy the TXT values from Lettr to Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to TXT.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix). For example, paste only scph0126._domainkey.mailing.
  4. Copy the Value from Lettr and paste it into the Text field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. scph0126._domainkey.mailing, not scph0126._domainkey.mailing.company.com).

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Add TXT Record (DMARC)

The DMARC record tells receiving mail servers how to handle emails that fail authentication checks, protecting your domain from spoofing. Copy the TXT values from Lettr to Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to TXT.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix). For example, paste only _dmarc.mailing.
  4. Copy the Value from Lettr and paste it into the Text field (e.g. v=DMARC1;p=none;).
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. _dmarc.mailing, not _dmarc.mailing.company.com).

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Verify Your Sending Domain

After adding all three DNS records, go back to Lettr and click Verify DNS Records. DNS propagation can take up to 24–48 hours, though it typically completes within a few minutes.

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Inbound Domain Setup

An inbound domain allows Lettr to receive emails on your behalf. This requires three MX records that direct incoming mail to Lettr’s mail servers.

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Add Inbound Domain to Lettr

To create an Inbound domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Inbound Domains
  3. Click Create Inbound Domain
  4. Enter your desired inbound subdomain (e.g. inbound.company.com)
  5. Click Create Domain.
Click on your new domain in the Inbound Domains list. This will display the MX records that need to be configured.

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Add MX Records

MX records tell other mail servers where to deliver emails addressed to your domain. Copy the MX values from Lettr to Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to MX.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix). For example, paste only inbound.
  4. Copy the first MX record value from Lettr (e.g. rx1.sparkpostmail.com) and paste it into the Mail Server field.
  5. Set Priority to 10.
  6. Click Save.
  7. Repeat this process for the second (rx2.sparkpostmail.com) and third (rx3.sparkpostmail.com) MX records, each with priority 10.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. inbound, not inbound.company.com).
Adding MX records to a domain or subdomain will route all incoming email for that address to Lettr. Use a dedicated subdomain (e.g. inbound.company.com) to avoid affecting your primary email.

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Verify Your Inbound Domain

After adding all three MX records, go back to Lettr and click Verify DNS Records. DNS propagation can take up to 24–48 hours, though it typically completes within a few minutes.

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Tracking Domain Setup

A tracking domain allows Lettr to track email opens and link clicks using your own custom domain instead of the default Lettr tracking domain. This requires two CNAME records: one for the SSL certificate and one for routing tracking traffic to Lettr’s infrastructure.

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Add Tracking Domain to Lettr

To create a Tracking domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Tracking Domains
  3. Click Create Tracking Domain
  4. Enter your desired tracking subdomain (e.g. tracking.company.com)
  5. Click Create Domain
Click on your new domain in the Tracking Domains list. This will display the CNAME records that need to be configured.

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Add SSL Certificate CNAME Record

The SSL Certificate CNAME record provisions an SSL certificate for your custom tracking domain, enabling secure HTTPS connections for tracked links. Add the record in Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to CNAME.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix).
  4. Copy the Value from Lettr and paste it into the Alias Data field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. tracking, not tracking.company.com).

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Add Traffic CNAME Record

The Traffic CNAME record routes click and open tracking requests from your custom domain to Lettr’s tracking servers. Add the record in Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to CNAME.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix).
  4. Copy the Value from Lettr and paste it into the Alias Data field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. tracking, not tracking.company.com).

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Verify Your Tracking Domain

After adding both CNAME records, go back to Lettr and click Verify DNS Records.

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Storage Domain Setup

A storage domain lets you serve email assets (images, attachments) from your own custom domain instead of the default Lettr storage URL. This requires two TXT records for certificate validation and ownership verification, and a CNAME record for routing asset requests to Lettr’s storage infrastructure.

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Add Storage Domain to Lettr

To create a Storage domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Storage Domains
  3. Click Create Storage Domain
  4. Enter your desired storage subdomain (e.g. assets.company.com)
  5. Click Create Domain
Click on your new domain in the Storage Domains list. This will display the TXT and CNAME records that need to be configured.

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Add TXT Record (Certificate Validation)

The Certificate Validation TXT record provisions an SSL certificate for your custom storage domain, enabling secure HTTPS delivery of email assets. Add the record in Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to TXT.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix).
  4. Copy the Value from Lettr and paste it into the Text field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion, just as with the CNAME record above.

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Add TXT Record (Hostname Pre-validation)

The Hostname Pre-validation TXT record verifies ownership of the storage domain before Lettr provisions a custom hostname for it. Add the record in Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to TXT.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix).
  4. Copy the Value from Lettr and paste it into the Text field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion, just as with the CNAME record above.

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Add CNAME Record (Domain Routing)

The Domain Routing CNAME record routes asset requests from your custom domain to Lettr’s storage infrastructure. Add the record in Squarespace:
  1. Click Add record in the DNS Settings panel.
  2. Set Type to CNAME.
  3. Copy the Hostname from Lettr and paste it into the Host field (without your domain suffix).
  4. Copy the Value from Lettr and paste it into the Alias Data field.
  5. Click Save.
Squarespace automatically appends your domain to the Host field. Always paste only the subdomain portion (e.g. assets, not assets.company.com).

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Verify Your Storage Domain

After adding all three records, go back to Lettr and click Verify DNS Records.

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Troubleshooting

Squarespace automatically appends your domain to the Host field. If you paste the full hostname (e.g. mailing.company.com), the resulting record will be mailing.company.com.company.com, which will fail verification.Always paste only the subdomain portion (e.g. mailing, scph0126._domainkey.mailing, _dmarc.mailing).
Squarespace DNS propagation can take up to 24–48 hours. If verification fails after adding records, check the following:
  • Wait at least 2–4 hours before your first verification attempt.
  • Confirm the records exist using command-line tools:
# Check CNAME record
dig CNAME mailing.yourdomain.com +short

# Check DKIM record
dig TXT scph0126._domainkey.mailing.yourdomain.com +short

# Check DMARC record
dig TXT _dmarc.mailing.yourdomain.com +short

# Check MX records (inbound)
dig MX inbound.yourdomain.com +short

# Check tracking domain CNAME
dig CNAME track.yourdomain.com +short

# Check storage domain CNAME
dig CNAME assets.yourdomain.com +short
Squarespace only supports custom DNS records for domains purchased or managed through Squarespace. If you are unable to add records, confirm that your domain is managed by Squarespace. If it is registered elsewhere, consider transferring it to Squarespace or pointing your nameservers to Squarespace before adding records.
Squarespace will display a “This host is already in use” error if you attempt to add a second TXT record with an identical Host value. Each hostname can only hold one TXT record in Squarespace’s DNS panel (with the exception of SPF records, which Squarespace merges automatically).If you need to add multiple TXT records for the same subdomain, consider managing DNS with a provider that supports multiple TXT records on the same hostname, such as Cloudflare or DigitalOcean.
A common mistake is selecting the wrong record type:
RecordCorrect Type
Sending verificationCNAME
DKIMTXT
DMARCTXT
Inbound mailMX
Tracking SSL certificateCNAME
Tracking trafficCNAME
Storage certificate validationTXT
Storage hostname pre-validationTXT
Storage domain routingCNAME
The DKIM TXT value is a long string. After saving the record, re-open the DNS Settings panel and confirm the full value is displayed. If it appears truncated, delete the record and re-add it, pasting the full value carefully.
If your records are saved in Squarespace but not resolving, confirm that your domain registrar is pointing to Squarespace’s nameservers. You can check this with:
dig NS yourdomain.com +short
The output should include Squarespace nameservers (e.g. ns1.squarespace-dns.com, ns2.squarespace-dns.com). If it shows a different provider’s nameservers, update them at your domain registrar.
If your DNS records are correctly configured (confirmed with dig or dnschecker.org) and verification still fails after 48 hours, contact Lettr support at support@lettr.com or through the in-app chat. Include your domain name and the output of the dig commands above.

Sending Domains

Learn about sending domain setup, SPF, DKIM, and DMARC.

Inbound Domains

Configure MX records to receive emails with Lettr.

Tracking Domains

Set up a custom tracking domain for click and open tracking.

Storage Domains

Serve email assets from your own custom domain.

Domains Overview

Understand domain types and how they work in Lettr.

Domain Verification Failures

Troubleshoot common DNS configuration and propagation issues.