SPF for Mailchimp: Email Authentication Setup Guide

Mailchimp is one of the most widely used email marketing platforms. Proper email authentication—including SPF—helps your campaigns reach subscribers' inboxes instead of spam folders. Here's how to set up SPF for Mailchimp.

How Mailchimp Handles SPF

Mailchimp's approach to SPF is slightly different from transactional email services. By default, Mailchimp sends emails on behalf of your domain using their own infrastructure. They handle SPF authentication through their servers.

When you set up custom domain authentication in Mailchimp (which you should), they use a combination of:

• CNAME records for DKIM signing
• Their existing SPF through the return-path domain they control

This means in many cases, you don't need to add a specific Mailchimp include to your SPF record. However, understanding how it works helps you troubleshoot issues and optimize deliverability.

The Mailchimp SPF Include

If you want to explicitly authorize Mailchimp in your SPF record, use:

include:servers.mcsv.net

This authorizes Mailchimp's (Mandrill's) mail servers to send email for your domain.

Setting Up Domain Authentication in Mailchimp

For best results with Mailchimp, complete their domain authentication process:

Step 1: Access domain settings

1. Log into Mailchimp
2. Go to Account → Domains
3. Click "Add & Verify Domain" or select an existing domain

Step 2: Add DNS records

Mailchimp provides two types of records:

CNAME records for DKIM:

k1._domainkey.yourdomain.com → dkim.mcsv.net

These enable DKIM signing, which cryptographically verifies your emails.

Verification record: Mailchimp may also provide a TXT record to verify domain ownership.

Step 3: Verify in Mailchimp

After adding the DNS records, return to Mailchimp and click "Verify." It may take a few minutes to hours for DNS changes to propagate.

Adding Mailchimp to Your SPF Record

If you choose to add Mailchimp to your SPF record explicitly:

Basic SPF with Mailchimp:

v=spf1 include:servers.mcsv.net ~all

Combined with other services:

v=spf1 include:_spf.google.com include:servers.mcsv.net ~all

Steps to add:

1. Log into your DNS provider
2. Find your existing TXT record starting with v=spf1
3. Add include:servers.mcsv.net before the ~all
4. Save and wait for propagation

Do You Need SPF for Mailchimp?

Here's when you might or might not need to add Mailchimp's SPF include:

You probably don't need it if:

• You've completed Mailchimp's domain authentication (DKIM)
• Your emails show SPF pass in headers (via Mailchimp's return-path)
• You're using Mailchimp's default sending setup

You should add it if:

• You're using a custom return-path domain
• You're sending through Mandrill with custom envelope settings
• Your DMARC policy requires SPF alignment (strict mode)
• You're troubleshooting deliverability issues

Check your email headers to see the current SPF status. If it shows pass, your current setup is working.

Verifying Your Mailchimp Setup

After configuring authentication, verify everything works:

1. Check Mailchimp's verification status

In Account → Domains, verified domains show a green checkmark. If verification failed, Mailchimp explains what's missing.

2. Send a test campaign

Send a test email to yourself. In Gmail, click the three dots → "Show original" and look for:

Authentication-Results: ...
  dkim=pass
  spf=pass

3. Check the return-path

In the headers, look for the Return-Path. If it's a Mailchimp domain (like bounce.mailchimp.com), SPF authentication happens against that domain, not yours.

4. Use Mailchimp's inbox preview

Mailchimp's inbox preview tool can help identify authentication issues before you send to your full list.

Common Mailchimp SPF Issues

SPF shows neutral or softfail

If your emails show SPF issues:

1. Check the return-path domain — SPF validates the return-path, not the From address. If Mailchimp controls the return-path, SPF is their responsibility.

2. Verify DKIM is working — With DKIM passing, many email providers will deliver even if SPF is neutral.

3. Consider adding the SPF include — If you need SPF alignment, add include:servers.mcsv.net to your record.

Domain verification failing

• Ensure DNS records are added exactly as Mailchimp specifies
• Wait longer for propagation (up to 48 hours)
• Check for typos in CNAME records
• Verify you're editing the correct domain's DNS

Emails going to spam despite authentication

Authentication is one factor among many. Also check:

• List quality (are recipients engaged?)
• Content (spam trigger words, image-to-text ratio)
• Sending frequency and volume
• Your domain and IP reputation

Mailchimp with Other Email Services

Most businesses use Mailchimp alongside other email tools. Here are common combinations:

Mailchimp + Google Workspace:

v=spf1 include:_spf.google.com include:servers.mcsv.net ~all

Mailchimp + Microsoft 365:

v=spf1 include:spf.protection.outlook.com include:servers.mcsv.net ~all

Mailchimp + SendGrid + Google:

v=spf1 include:_spf.google.com include:sendgrid.net include:servers.mcsv.net ~all

Watch your DNS lookup count when combining services. See our guide on the SPF 10 DNS lookup limit.

Mailchimp Transactional (Mandrill)

If you use Mandrill for transactional emails, the SPF configuration is the same:

include:servers.mcsv.net

For Mandrill, you should also:

1. Verify your sending domain in the Mandrill dashboard
2. Add the DKIM records Mandrill provides
3. Configure your application to send through Mandrill's API or SMTP

Mandrill's documentation provides specific setup instructions for various platforms and languages.

Complete Email Authentication for Mailchimp

For maximum deliverability, set up all three authentication methods:

SPF — Optionally add include:servers.mcsv.net to your record

DKIM — Required. Add the CNAME records from Mailchimp's domain authentication

DMARC — Once DKIM is verified, add a DMARC record to control how receivers handle authentication failures

Mailchimp's email authentication works best with DKIM as the primary method. SPF is secondary but can help with strict DMARC policies.

Monitor Your SPF Records

Checking once is good. Monitoring continuously is better. The Email Deliverability Suite watches your SPF, DKIM, DMARC, and MX records daily and alerts you when something breaks.