From time to time, companies ask us security questions about MailChimp. In general, we don't like to expose much information about our security practices, because it only helps the very people we're securing ourselves against. But we realize security is very important to you, so we've decided to carefully post some answers to the questions we feel are most important for our customers to know.

Data Center Security

• MailChimp delivers about 2.5 billion emails a month for more than 1.6 million users. We use multiple MTAs, placed in different world-class data centers, around the US.
• Our data centers manage physical security 24/7 with biometric scanners, and the usual high tech stuff that data centers always brag about.
• We have DDOS mitigation in place at all our data centers
• We have a documented "in case of nuclear attack on a data center" infrastructure continuity plan.

Protection from Data Loss, Corruption

• All large account databases are kept separate and distinct to prevent corruption and overlap. Smaller user accounts and our free user accounts are placed into the same large database for speed. As accounts grow in list size, they are migrated into their own distinct databases.
• Account data is mirrored and backed up regularly off site.

Application Level Security

• MailChimp account passwords are encrypted. Our own staff can't even view them. If you lose your password, it can't be retrieved - it must be reset.
• All login pages (from our website and mobile website) pass data via SSL
• The entire MailChimp application is encrypted with SSL
• Login pages have brute force protection
• Logins via the MailChimp API have brute force protection
• We perform regular security penetration tests, using different vendors (for a "2nd opinion").The tests involve high level server penetration tests, in-depth testing for vulnerabilities inside the application, and social engineering drills.

Mobile App Security

• Sensitive data on iPhone apps are stored in Keychain for security
• Sensitive data is transmitted via SSL
• Pending: Truste Certification for GoldenMonkeys iPhone app

Internal IT Security

• The MailChimp office is secured by keycard access, and is monitored with infrared cameras throughout.
• Our office network has extremely limited exposure to Microsoft Windows. And that's all we have to say about that.

Internal Protocol & Education

• Employees are taught not to vilify hackers, which gives the false impression that in the end, the bad guys always lose and there will be a happy ending. Hackers do what they do for money—this is business for them. So we view them as competition. And competition never dies.
• All new employees on teams that have access to customer data (such as tech support and our engineers) undergo criminal history and credit background checks prior to employment.

• The Art of Deception, by Kevin Mitnick, is required reading for all new employees who deal directly with customer data. Fatal System Error, by Joseph Menn, is extra credit.
• All employees sign a Privacy Safeguard Agreement outlining their responsibility in protecting customer data
• All new employees are given security guidelines for using social media, including information about social engineering.
• We have an employee termination ("aka change management") process in place
• In order to protect our company from a variety of different losses, MailChimp has established a comprehensive insurance program. This program has been designed to cover us for standard business losses that all businesses can face as well as those losses that are unique to what we do in the technology industry. Additionally, we have selected a carrier that is financially strong and purchased substantial limits for the following general coverages.
  • Property and Business Interruption
  • Commercial General Liability
  • Workers Compensation and Employers Liability
  • Business Automobile
  • Umbrella Liability
  • International Property and Liability
  • Technology Errors & Omissions Liability
  • Management Liability

Protecting Ourselves Against You

Yes, you heard that correctly. We can secure ourselves like Fort Knox, but if your computer gets compromised and someone gets into your MailChimp account, that's not good for either of us.

• We monitor and will automatically suspend accounts for signs of irregular or suspicious login activity.
• Certain changes to your account, such as your password, trigger email notifications to the account holder.
• Omnivore monitors account and campaign activity for signs of abuse
• In addition to our scalable algorithms, we employ another layer of human reviewers, who monitor for anomalous account and email activity

Investing in Your Privacy

• Our General Counsel / Chief Privacy Officer works with our developers to make sure our features comply with applicable international spam and privacy laws.
• We retain a law firm in the UK to consult on EU privacy issues.
• Our privacy policy is monitored by TRUSTe and is EU SafeHarbor compliant.
• We are members of the ESPC, OTA, and MAAWG

* A Note to Hackers (and lawyers)

Hi there. Yes, we know that none of the stuff we listed above means we're totally hacker safe or impenetrable. But our customers constantly ask for this stuff, so we're listing (some of) what we do for security. If you find a vulnerability, please get in touch.