Getting Into the Inbox
MailChimp employs a highly advanced delivery infrastructure and a smart delivery team. We watch our rates like a hawk, and you should too. But deliverability is more than numbers and charts. Here are the facts:
Omnivore
Our powerful 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 desk internally monitors our system with Cloudmark and Barracuda, the same powerful filtering technology that major ISPs use to block spam.
Authentication
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, SPF, and Domain Keys automatically and free.
IP Address Ranges
Mailchimp uses hundreds of IP addresses located in multiple data centers, to protect our deliverability. 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, USA.net, Cox, Earthlink, and more.
Whitelists
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 active 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), and EEC (Email Experience Council).