To ensure your website can send emails using Google Apps, SendGrid, and Mailchimp, you need to configure your SPF (Sender Policy Framework) record correctly. Google Apps will handle incoming emails, while SendGrid and Mailchimp will manage outgoing marketing communications.

Understanding SPF Records

An SPF record is a DNS record that specifies which mail servers are permitted to send email on behalf of your domain. However, there is a strict limit of 10 DNS lookups for SPF records. If your SPF record exceeds this limit, you may encounter a PermError: Too many DNS lookups error when validating your SPF record.

Example SPF Record

Here’s an example of an SPF record that includes Google Apps, SendGrid, and Mailchimp:

v=spf1 a mx include:_spf.google.com include:sendgrid.net ~all

Important Note on Mailchimp

It is crucial to not include Mailchimp's SPF record (include:servers.mcsv.net) in your domain's SPF policy. This inclusion can lead to unnecessary DNS lookups and may cause you to exceed the 10-lookup limit, resulting in email delivery issues. Many domains mistakenly added this due to outdated guidance, but it is now advised to omit it.

Optimizing Your SPF Record

To optimize your SPF record:

  1. Avoid unnecessary includes: Only include services that are essential for your email sending.
  2. Flatten your SPF record: Instead of using multiple include statements, consider flattening your SPF record by directly listing the IP addresses of the services you use, if possible.
  3. Test your SPF record: Use tools like Kitterman's SPF Validator to check for errors and ensure compliance with the 10-lookup limit.

Conclusion

By carefully configuring your SPF record and avoiding unnecessary includes, you can ensure that your emails are delivered successfully without hitting the DNS lookup limit. Always keep your SPF record updated as your email services change.