Email deliverability for author newsletters in 2025

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Why this matters now

Gmail and Yahoo tightened sender rules. If you send to large lists or run swaps, your messages face tougher filtering. You need an authenticated email, low complaint rates, and a one-click unsubscribe option. SPF, DKIM, and DMARC are the core items. When one fails or does not align with your From domain, inbox placement suffers. The fix is straightforward once you know the order of operations.

What counts as a bulk sender

Gmail treats you as a bulk sender when you hit large volumes in a day. Big launch pushes, swaps, and ARC blasts can tip you over. Even if you do not send daily, one significant push can trigger stricter checks.

What happens if you ignore this

You see soft bounces, spam placement, or outright rejection. Your open rates crater. Your list’s health declines because engaged readers do not see your messages.

SPF, DKIM, and DMARC in plain English

• SPF

SPF is a TXT record in DNS that lists servers allowed to send mail for your domain. The receiving server checks the connecting IP or sending service against your record. If it is listed, SPF passes.

• DKIM

DKIM adds a cryptographic signature to each message. Your sender signs with a private key and publishes a matching public key in DNS. Receivers verify the signature against your DNS record. If it validates, DKIM passes.

• DMARC

DMARC ties the results to your visible From domain. It specifies what to do if SPF or DKIM fails or does not align with the From domain. You can monitor, quarantine, or reject.

Alignment and why it matters

DMARC passes when at least one method, SPF or DKIM, passes and aligns. Alignment means the domain used by that method matches your From domain or a subdomain of it. If your ESP signs DKIM with your domain, DKIM alignment will still be effective even if SPF does not align.

The author’s tech stack at a glance

Squarespace

If you use Squarespace Email Campaigns, you add the DKIM records they provide and publish a DMARC record. Your goal is to achieve DKIM alignment and implement a DMARC policy.

Mailchimp

Authenticate your domain in Mailchimp with the two DKIM CNAME records. Publish DMARC at your domain. Mailchimp uses its own return path, so DKIM alignment is the usual path to DMARC pass.

Custom domain and Google Workspace or other SMTP

If you send emails from Google Workspace or your own SMTP server, you manage SPF, DKIM, and DMARC end-to-end. Publish Google’s SPF if you use Workspace. Generate a DKIM key in the Admin console. Add a DMARC policy. For other ESPs, such as SendGrid or Mailgun, follow their exact DNS values.

Step by step, start to finish.

Step 1: Audit Your Current Setup.

1. Send a test to a Gmail address. Open the message. Use Show original. Look for Authentication Results. You want spf=pass, dkim=pass, dmarc=pass.

2. List every system that sends using your From domain. Familiar sources include Mailchimp, Squarespace Email Campaigns, Google Workspace, SendGrid, Mailgun, BookFunnel transactional sends, store receipts, and help desk messages.

3. Open your DNS at your registrar or DNS host. Confirm that you have only one SPF record at the root level. Note any DKIM records. Note if a DMARC record exists at dmarc.yourdomain.com.

Step 2: Set up SPF

Rules

• Only one SPF TXT record at your root domain.

• Keep total DNS lookups under ten.

• Add includes for systems that use your domain’s return path.

Squarespace Email Campaigns

Focus on DKIM and DMARC. Squarespace signs DKIM. You do not need an SPF include for DMARC alignment when Squarespace uses its own return path.

Mailchimp

Please don’t add Mailchimp includes to SPF for alignment. Authenticate your domain in Mailchimp and rely on DKIM alignment.

Custom domains and Google Workspace example

TXT @
v=spf1 include:_spf.google.com ip4:203.0.113.25 include:sendgrid.net ~all

Could you replace the IP address and include the actual senders' values? The softfail operator ~all is standard. You can use -all only after you are sure all sending systems are covered.

Step 3: Set up DKIM

Squarespace

Could you add the DKIM CNAMEs or TXT records from Squarespace Email Campaigns? The record names often look like s1._domainkey and s2._domainkey. Wait for DNS to propagate. Then, verify inside Squarespace.

Mailchimp

Add the two CNAME records Mailchimp provides. Names typically resemble k2._domainkey and k3._domainkey, with values referencing DKIM hosts at Mailchimp. Please return to Mailchimp and click 'Authenticate' once the DNS has propagated.

Google Workspace and other ESPs

In Google Workspace, open the Admin console, create a DKIM key, and publish the TXT record at selector._domainkey.yourdomain, then turn on signing. For SendGrid, Mailgun, and similar platforms, add the CNAMEs provided by them. Verify inside the platform.

Step 4: Set up DMARC

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Start with monitoring

TXT _dmarc
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; fo=1; adkim=s; aspf=s

This collects reports without changing delivery. adkim=s and aspf=s require strict alignment, which helps you catch misconfigurations early.

Move to quarantine in stages.

TXT _dmarc
v=DMARC1; p=quarantine; pct=25; rua=mailto:dmarc@yourdomain.com; fo=1; adkim=s; aspf=s

pct controls how much failing mail gets quarantined. Raise pct to 100 when you see clean reports.

Enforce with rejection

TXT _dmarc
v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com; fo=1; adkim=s; aspf=s

Switch to reject after every sending system passes and aligns. This blocks spoofed messages and maintains a clean domain reputation.

Step 5: Meet the rest of Gmail’s requirements

One click unsubscribe

Turn on list unsubscribe in your ESP. Ensure your template displays a visible unsubscribe link. This reduces complaints and ensures compliance.

Complaint rate targets

You can track spam complaints in your ESP and Postmaster tools, if available. Keep complaints low by mailing engaged readers, pruning inactive accounts, and setting clear expectations on your sign-up forms.

List hygiene and segmentation

Use double opt-in for new subscribers. Remove hard bounces right away. Suppress readers who have not opened in months, then run a short re-engagement series before permanently removing them.

Working examples

Example DNS for an author on Squarespace

1. DKIM
   CNAME s1._domainkey.yourdomain → value from Squarespace
   CNAME s2._domainkey.yourdomain → value from Squarespace

2. DMARC
   TXT _dmarc → v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; adkim=s; aspf=s

Example DNS for an author on Mailchimp

1. DKIM
   CNAME k2._domainkey.yourdomain → dkim host from Mailchimp
   CNAME k3._domainkey.yourdomain → dkim host from Mailchimp

2. DMARC
   TXT _dmarc → v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; adkim=s; aspf=s

Example DNS for an author on Google Workspace

1. SPF
   TXT @ → v=spf1 include:_spf.google.com ~all

2. DKIM
   TXT google._domainkey → k=rsa; p=your_public_key

3. DMARC
   TXT _dmarc → v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; adkim=s; aspf=s

The simple pass checklist

Use this quick list before any big send.

• From address uses your custom domain, not a free mailbox.
• One SPF TXT record at root, under the ten lookup limit.
• DKIM signing is on for each sender you use.
• DMARC TXT exists at _dmarc with p=none or stronger.
• At least one aligned pass, SPF or DKIM.
• One-click unsubscribe is present and working.
• Visible postal address in the footer, clear permission reminder, and a working unsubscribe link.
• Complaint rate stable and low.
• Bounces are removed fast. Inactives are segmented or suppressed.
• Test message shows spf=pass, dkim=pass, dmarc=pass in Gmail’s original headers.

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Troubleshooting matrix

1. Symptom
   dmarc=fail, dkim=pass, spf=fail

2. Likely cause
   DKIM passes, but the d= domain does not match your From domain

3. Fix
   Change the DKIM to sign with your domain or switch the From to the domain that is signing. Send a new test and confirm alignment.

1. Symptom
   dmarc=fail, dkim=fail, spf=pass

2. Likely cause
   SPF passes for a third party, but the SPF domain does not align with your From domain

• Fix
  Use DKIM alignment. Enable DKIM signing for your domain at the ESP. Keep SPF for server authorization, but rely on DKIM for DMARC alignment.

1. Symptom
   Gmail shows “via” next to your From name

2. Likely cause
   Your domain is not authenticated at the ESP

3. Fix
   Add the ESP’s DKIM CNAMEs and authenticate the domain in the ESP’s settings. Send a test again.

1. Symptom
   ESP says pending authentication

2. Likely cause
   DNS propagation delay or incorrect host names

3. Fix
   Wait up to 24 hours. Make sure host names include the selector and _domainkey. Remove duplicate or conflicting records. Publish only one SPF TXT at the root.

1. Symptom
   Squarespace campaigns land in spam

2. Likely cause
   DKIM or DMARC is missing

3. Fix
   Add Squarespace DKIM records. Publish a DMARC record. Run a new test and verify alignment.

Testing tools and how to read results

Gmail headers

Send a test to a Gmail inbox. Open the message. Choose Show original. Look for Authentication Results. You want spf=pass, dkim=pass, dmarc=pass. If dmarc=fail, could you check which method is missing alignment?

Your ESP’s preflight checks

Most platforms provide preflight tests. Use them before large campaigns. Fix authentication errors before you mail a complete list.

DMARC aggregate reports

DMARC reports indicate who is sending emails using your domain and whether messages pass SPF or DKIM with proper alignment. Route rua to a dedicated inbox and process the XML with a parser or a monitoring service. Review weekly to catch new senders and misconfigurations.

Ongoing maintenance routine

Weekly

• Review DMARC aggregate reports.

• Remove hard bounces and spam traps.

• Suppress readers who have not opened in months.

Monthly

• Send an authentication test and re-check headers.

• Confirm list unsubscribe headers still appear on all promotional campaigns.

• Review complaint rates and adjust targeting and cadence.

Quarterly

• Re-audit your DNS. Confirm only one SPF record.

• Keep SPF lookups under ten.

• Rotate DKIM keys if your ESP supports it.

• Validate that all new tools, plugins, and transactional systems are authenticated and aligned.

Conclusion

Deliverability in 2025 rewards clean authentication and reader-first sending habits. Set up SPF, DKIM, and DMARC in the order above. Use DKIM alignment as your anchor, then bring SPF and DMARC into full enforcement. Add one-click unsubscribe options, prune inactive users, and test headers before major pushes. With this checklist and matrix, your author newsletter reaches inboxes, not spam folders.

FAQs

How strict should my first DMARC policy be

Start with p=none to collect reports. Fix issues you find. Move to quarantine with the percentage threshold (PCT) set to a lower value, then raise it to 100. Enforce with p=reject once every sender passes with alignment.

Do I need SPF includes for Mailchimp?

No. Could you unlock your domain in Mailchimp with the DKIM CNAME records? Mailchimp’s DKIM alignment carries DMARC. Keep your SPF record focused on systems that use your domain’s return path.

Does Squarespace support SPF, DKIM, and DMARC?

You manage DNS in your Squarespace domain settings or at your registrar. Add Squarespace DKIM records and publish a DMARC TXT at _dmarc—test headers to confirm pass and alignment.

What if I use Google Workspace for the author’s email

Publish Google’s SPF include. Generate a DKIM key in the Admin console and turn on signing. Add a DMARC policy with rua reporting. Confirm spf=pass, dkim=pass, dmarc=pass on a Gmail test.

What else improves inbox placement beyond authentication

Make unsubscribing easy. Mail consistently. Send to people who asked for your emails. Remove inactives. Keep complaint rates low. Use double opt-in and clear permission reminders in your signup forms.