MailChimp is a marketing automation platform and an email marketing service and a trading name of its operator, Rocket Science Group, an American company founded in 2001 by Ben Chestnut and Dan Kurzius. MailChimp began as a paid service and added a freemium option in 2009. Within a year its user base had grown from 85,000 to 450,000. By June 2014, it was sending over 10 billion emails per month on behalf of its users. In 2017, the company was gaining 14,000 new customers every day. The company is still owned by its cofounders and has never accepted venture capital funds.
In 2016, MailChimp was ranked No. 7 on the Forbes Cloud 100 list. In February 2017, the company was named one of Fast Company's Most Innovative Companies of 2017. In August 2017, It was reported that, MailChimp would be opening offices in Brooklyn and in Oakland, California.