MailChimp’s abuse-detection technology keeps our system clean by predicting bad behavior in a campaign before it even gets out the door. Omnivore is always at work in the background, analyzing emails, processing new data, and preventing abuse on a massive scale.

Abuse Monitoring

Our abuse team monitors our system, supplementing the automated efforts of Omnivore, our in-house abuse-prevention initiative. Our delivery team monitors IP reputation, routes good traffic around blocked IPs, and manages bounces across our user base.


Large corporations and financial institutions use authentication to prove their emails aren't forgeries so they don’t get blocked by overly suspicious filters. MailChimp supports DKIM, SenderID, and SPF automatically and free.

IP Address Ranges

To protect our deliverability, MailChimp uses hundreds of IP addresses located in multiple data centers. These IPs are grouped into different reputation levels based on list‑member activity. We monitor our IP acceptance rates with ReturnPath, a leading third‑party deliverability vendor, and depending on which group of IPs an email is sent from, inbox acceptance rates range from 96‑99 percent.

Bounce Management

We don’t just analyze your bouncebacks to clean your list—our abuse monitoring system detects potential delivery issues by actively scanning bounce logs for cryptic messages from spam filters and email servers.

ISP Feedback Loops

We’re registered with all the major ISPs to receive alerts whenever your recipients report your campaigns as junk or spam. If that happens, we instantly unsubscribe those members from your list in order to keep you (and MailChimp) from being blocked in the future. We’re on feedback loops with AOL, Hotmail, Comcast, Yahoo,, Cox, Earthlink, and more.


Even though most ISPs are transitioning to feedback loops, some still employ whitelists. MailChimp is registered with them and actively works to maintain our whitelisted status.

Industry Memberships

We stay current on industry and technology standards as members in email and ISP organizations including the ESPC (Email Sender and Provider Coalition), AOTA (Authentication and Online Trust Alliance), MAAWG (Messaging Anti-Abuse Working Group), EEC (Email Experience Council), and Signal Spam.

Messaging Anti-Abuse Working Group
Signal Spam