Email Setup Wizard

Fastmail + Squarespace Domains

Set up Fastmail email on Squarespace Domains

The records Fastmail needs, written with the field names Squarespace Domains uses (Name, Mail Server, Text, Data), in the order to add them.

  • 4 steps
  • 7 DNS records
  • Sources checked October 21, 2026

Before you start

  1. Have your Fastmail account ready. Some values are unique to your account and come from the Fastmail Settings.
  2. Open DNS at Squarespace Domains: Open the domains dashboard (account.squarespace.com/domains). Click your domain. Click DNS, then DNS Settings.
  3. Keep both tabs open and add the records below one at a time.

Records to add

Copy each value with the button next to it. Rows marked “Copy from Fastmail Settings” are unique to your account.

MX records Where incoming email goes Type MX Name @ Value in1-smtp.messagingengine.com Priority 10 TTL 4 hours
MX records Where incoming email goes Type MX Name @ Value in2-smtp.messagingengine.com Priority 20 TTL 4 hours
SPF record Which servers may send as you Type TXT Name @ Value v=spf1 include:spf.messagingengine.com ?all Priority n/a TTL 4 hours
DKIM A signature on every message Type CNAME Name fm1._domainkey Value fm1.yourdomain.com.dkim.fmhosted.com Priority n/a TTL 4 hours
DKIM A signature on every message Type CNAME Name fm2._domainkey Value fm2.yourdomain.com.dkim.fmhosted.com Priority n/a TTL 4 hours
DKIM A signature on every message Type CNAME Name fm3._domainkey Value fm3.yourdomain.com.dkim.fmhosted.com Priority n/a TTL 4 hours
DMARC record What to do with fakes · recommended Type TXT Name _dmarc Value v=DMARC1; p=none; Priority n/a TTL 4 hours

Step by step in Squarespace Domains

Point your MX records

MX records tell every other mail server where to deliver email for your domain. They must point to your provider and nowhere else.

Type
MX
Name
@
Priority
10
Mail Server
in1-smtp.messagingengine.com
Type
MX
Name
@
Priority
20
Mail Server
in2-smtp.messagingengine.com

In Squarespace Domains

  1. Click Add record.
  2. Re-enter your password (or confirm with two-factor authentication) if asked, then click Continue.
  3. Set Type to MX, then fill in Name, Priority and Mail Server.
  4. Click Save. Add one record per mail server, each with its own priority.
  5. Repeat for each MX record above.

Add the SPF record

SPF is a TXT record that lists the services allowed to send email from your domain, so receivers can spot forgeries.

Type
TXT
Name
@
Text
v=spf1 include:spf.messagingengine.com ?all
  • This is the exact value from Fastmail's manual DNS guide, which ends in ?all (neutral).

In Squarespace Domains

  1. Scroll to Custom Records and click Add record.
  2. Re-enter your password (or confirm with two-factor authentication) if asked, then click Continue.
  3. Set Type to TXT, then fill in Name and Text.
  4. Click Save.

Set up DKIM

DKIM publishes a public key so receivers can confirm your messages really came from you and were not changed on the way.

Type
CNAME
Name
fm1._domainkey
Data
fm1.yourdomain.com.dkim.fmhosted.com
Type
CNAME
Name
fm2._domainkey
Data
fm2.yourdomain.com.dkim.fmhosted.com
Type
CNAME
Name
fm3._domainkey
Data
fm3.yourdomain.com.dkim.fmhosted.com

In Squarespace Domains

  1. Scroll to Custom Records and click Add record.
  2. Re-enter your password (or confirm with two-factor authentication) if asked, then click Continue.
  3. Set Type to CNAME, then fill in Name and Data.
  4. Click Save.
  5. Repeat for each CNAME record above.

Add the DMARC record (recommended)

DMARC tells receivers what to do with mail that fails SPF and DKIM, and where to send reports about it.

Type
TXT
Name
_dmarc
Text
v=DMARC1; p=none;

In Squarespace Domains

  1. Scroll to Custom Records and click Add record.
  2. Re-enter your password (or confirm with two-factor authentication) if asked, then click Continue.
  3. Set Type to TXT, then fill in Name and Text.
  4. Click Save.

Check your setup

Once the records are saved, run a live check. We look up your domain in public DNS and tell you what is right, missing or wrong, with the fix in Squarespace Domains’s words.

We only read public DNS records. Nothing is stored.

Common mistakes with Fastmail on Squarespace Domains

Adding fewer than three DKIM records

Fastmail signs with three selectors (fm1, fm2, fm3). All three CNAMEs are required.

Adding a second SPF record

Only one record may start with v=spf1. Merge Fastmail's include into the existing one.

Squarespace Domains: Change your Squarespace login first

If you sign in to Squarespace with an address at this domain, change your account email before deleting MX records, or you could lock yourself out.

Squarespace Domains: SPF entries are merged for you

Each SPF value added as its own custom record is merged into one SPF record. Refresh the page to see the merged result. If you get a Custom records not saved error, delete the existing SPF records and add them again.

Squarespace Domains: Only one DMARC record

A domain can have only one DMARC record. Email forwarding rules add one automatically, so merge into it rather than adding a second.

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Fastmail on Squarespace Domains: questions

Where do I add Fastmail DNS records in Squarespace Domains?

Open the domains dashboard (account.squarespace.com/domains). Click your domain. Click DNS, then DNS Settings. Add each record there, one at a time.

What goes in the Name field at Squarespace Domains?

Enter @ for records on your bare domain, such as MX and SPF. For the others, enter only the part before your domain, for example fm1._domainkey. Squarespace Domains adds your domain automatically.

Do I need to delete my existing MX records at Squarespace Domains?

Yes. Mail servers deliver to every MX record you publish, so keep only the Fastmail MX records and delete the rest. If you sign in to Squarespace with an address at this domain, change your account email before deleting MX records, or you could lock yourself out.

Where do I get my Fastmail DKIM record?

Fastmail DKIM records are CNAME records whose value includes your domain, for example fm1.yourdomain.com.dkim.fmhosted.com. Copy the exact values for your domain from the table on this page.

How long until Fastmail email works on Squarespace Domains?

Squarespace says DNS changes can take 24 to 48 hours to update.

Sources

Every value and step on this page comes from these official pages. Dashboards change, so if something doesn’t match what you see, tell us.

Fastmail on other hosts

Other email providers on Squarespace Domains