About Mailchimp Email Delivery Rates

Many factors impact email delivery rates. The time it takes to deliver your email campaign to your entire audience depends on the sending server's reputation, the email's content, and its recipients. Email send times will also depend on the size of your audience, and on the current mail queue at Mailchimp.

In this article, you'll learn about the factors that impact the delivery of your campaigns.

Sending server reputation

Mailchimp's sending reputation directly affects the delivery of your emails. If a sending server's IP address is flagged by spam filters, receiving servers will block emails from that address.

We work hard to maintain a great sending reputation by following best practices and giving our users the tools they need to stay compliant with anti-spam laws. When you send a campaign, our automated abuse-prevention system, Omnivore, scans your campaign and analyzes addresses that could affect the delivery of your campaign.

These measures help protect your sending reputation and ours, and help keep your campaigns out of spam filters.

Terms of Use and Anti-Spam Requirements
About Omnivore

Campaign content and audience management

The only thing Mailchimp can control is our infrastructure. Beyond that, it's up to you to follow best practices for campaign content and contact collection.

Here are a few ways you can improve the deliverability of your email campaigns.

• Create email content that's compliant with our Terms of Use and consistent with your brand.
• Maintain a healthy audience with good email subscription practices.
• Use merge tags to personalize the "To" field in your emails with your subscribers' names.
• Ask your subscribers to add you to their address book. Spam filters are less likely to flag your email if your subscribers have saved you as a contact.

Requirements and Best Practices for Audiences
Getting Started with Merge Tags

About receiving servers

Receiving servers get your campaigns from the sending servers at Mailchimp and transfer them to your recipients' inboxes. Once you've sent a campaign through Mailchimp, the receiving server analyzes your email's content and sender information before it allows the email to reach the recipient. Some servers have more aggressive spam filters and firewalls in place that can delay or prevent delivery. Unfortunately, Mailchimp has no control over this step in the process.

Most receiving servers have spam filters that use sophisticated algorithms to analyze lots of emails with a long list of criteria. If something about your email triggers a spam filter, it will likely delay delivery while it performs further analysis, but generally, your campaign would need to have multiple triggers to get filtered as spam.

About Spam Filters
About Email Firewalls