Do I need to include Mailchimp's SPF record in my domain's SPF if Mailchimp handles the bounce address?
Summary
What email marketers say6Marketer opinions
Email marketer from DMARCly shares that using Mailchimp's 'own' return-path (bounce) domain will result in your emails passing SPF, as Mailchimp configures SPF for that domain. In this scenario you don't need to add their SPF record to your domain.
Email marketer from StackOverflow explains that it's generally unnecessary to include Mailchimp's SPF if they are managing the bounce domain. Focusing on DKIM and ensuring it's properly set up is a better approach.
Email marketer from Reddit forum explains that after researching they removed the mailchimp SPF records, as they are only needed if you are using your own subdomain for bounces and handles the bounce processing yourself - otherwise use their DKIM records
Email marketer from EasyDMARC shares that with Mailchimp, you typically don't need to add their SPF record to yours if they handle the bounce address. Instead, focus on DKIM authentication for better results and deliverability.
Email marketer from Email Geeks explains that SPF will fail DMARC if the SPF domain (mcsv.net for Mailchimp bounces) is not aligned with the RFC5322.From domain (the client's domain). Since you can never pass SPF at Mailchimp for the customer domain (the SPF domain will always be mcsv.net), you've done all you can.
Email marketer from Email on Acid explains that if you're using Mailchimp’s default setup, Mailchimp handles the SPF configuration automatically, so you do not have to manage it.
What the experts say4Expert opinions
Expert from Word to the Wise explains that if Mailchimp is handling the bounce address, using their domain, you typically do not need to include their SPF record in your own domain's SPF record.
Expert from Email Geeks clarifies that SPF is only about authenticating the bounce address, and you don't need to add every ESP you use to the SPF record for your corporate domain.
Expert from Email Geeks confirms that if the 5321 address is from Mailchimp and passing SPF for Mailchimp, you do not need to include servers.mcsv.net in your domain's SPF.
Expert from Email Geeks explains that for bulk mail, you should never need to include more than one ESP in an SPF record, as the 5321.from address should be unique to that ESP. Otherwise, you'll have issues with bounce handling.
What the documentation says3Technical articles
Documentation from Mailchimp Help Center explains that Mailchimp handles SPF automatically by using their own sending domain for the return-path. Therefore, you do not need to add a Mailchimp SPF record to your domain's DNS records when authenticating with DKIM.
Documentation from Google Workspace Admin Help specifies that SPF is used to verify the sender's domain. If Mailchimp is handling the bounce address with their own domain, their SPF records will be used for that part of the process, and your domain's SPF record is less relevant for emails sent via Mailchimp.
Documentation from SparkPost documentation explains that when using an ESP like Mailchimp, if they are handling the bounce address (Return-Path), you typically don't need to include their SPF record in your domain's SPF record. Their infrastructure will handle SPF authentication for the bounce domain.