Best practices for sending emails from a 3rd party vendor

Last updated May 10, 2024

What is changing?

The goal of these changes is to protect against spam and improve deliverability. In short, these changes include:

This is an accordion element with a series of buttons that open and close related content panels.

Stricter email authentication standards

Authenticating your outbound email helps the receiving mailbox provider (Google, Yahoo or Apple) know that a message actually came from your organization, or was sent on your behalf through a 3rd-party service like Mailchimp or Constant Contact. Find out more about email authenticity (DMARC).

Adding a one-click unsubscribe function

One-click unsubscribe is a user-friendly feature embedded directly within the email interface that lets subscribers easily opt out of mailing lists with a single click. This eliminates the user hunting for the unsubscribe link and navigating through several webpages to unsubscribe.

One-click unsubscribe empowers users by simplifying the unsubscribing process, giving them greater control over what lands in their inbox.

Marketing and promotional emails need to include clear unsubscribe links in the body of the text and support one-click unsubscribe in the message or email header (header: metadata included in every email), making it easier for users to opt out of future messaging.

Maintaining a low user-reported spam rate

UW–‍Madison senders must maintain a user-reported spam rate of less than 0.1%. This means out of every 1,000 emails from UW–‍Madison, only 1 can be marked as spam. The university could face various repercussions, from throttling to routing messages to spam folders to outright rejection of emails if we are over that threshold.

Our user-reported spam rate is calculated by collectively looking at all emails from UW–‍Madison.

This means all emails sent from our domain are evaluated together, and the user-reported spam rate is derived from this aggregate data. While your emails may pass email authentication measures, if other senders from our domain fail to meet those standards, it can adversely impact the reputation and deliverability of emails for our entire domain.

Thus, maintaining a low user-reported spam rate is incredibly important. Doing so helps ensure we’re protecting the reputation of email from UW–‍Madison.

What should you do?

We are here to help you determine whether your emails are compliant with the new requirements. If you think you may be impacted (or if you aren’t sure), contact us for an email authenticity consultation.

Request an email authenticity consultation

If you’re sending marketing/promotional emails, make sure your email sending platform or tool supports 1-click unsubscribe.

What if you do nothing?

If your emails from these services do not meet the new sending requirements, any of the following could occur.

Delays in delivery

Messages could experience delivery delays.


Your messages could be sent to the recipient’s spam folder.

Rejected messages

Messages could be rejected as undeliverable.

5 best practices to follow when sending emails

In addition to adhering to the new sending requirements, we recommend following these best practices when sending emails. The goal is to work together to protect the reputation of emails sent from UW–‍Madison.

  • Do not use an email address in the domain (e.g. with services other than UW–‍Madison Microsoft 365. Instead, we recommend you use an email address in a subdomain (e.g. with 3rd party services.
  • Follow vendor-supplied directions on how to approve an email address or domain for use with their service.
  • Make sure recipients have signed up to receive your mailings. You should have explicit opt-in consent from the people on your email list.
  • Provide recipients the option to unsubscribe from future mailings.
  • Refrain from repurposing contact lists. People are more likely to mark your messages as spam if they receive mail they aren’t expecting.

Resources & documentation

Want to learn more about these changes? Check out the resources below.

3rd party documentation

KnowledgeBase documents

The KnowledgeBase articles linked below outline steps to set up custom domain authentication for common 3rd party services. Doing so allows the 3rd party vendors to send DMARC-compliant emails from email addresses in your organization’s subdomain (e.g.