Mailchimp is an email and SMS marketing platform: a hosted service that stores a business's contact list and sends marketing messages to it. The Mailchimp trademark belongs to The Rocket Science Group. Contacts are kept in an audience; they arrive through signup and popup forms on the business's website, through imports, or through connected apps, and the business can divide them into segments.
In the web app, a user builds an email from pre-built or custom-coded templates, schedules it, and sends it to the whole audience or to one segment. Marketing automation flows send messages automatically according to rules the business sets. Reports show how each campaign performed. Mailchimp connects to more than 300 other apps, such as Shopify, WooCommerce, Stripe and Zapier, and offers a Marketing API and a Transactional API for developers.
Mailchimp is sold as a subscription. A free plan covers up to 250 contacts. The paid plans, Essentials, Standard and Premium, are priced by the number of contacts, and each plan limits the number of emails sent per month. SMS is a paid add-on.