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# How Mailchimp works

> What Mailchimp does for the businesses that use it, and what people use the Marketing API to do.

## What Mailchimp is for

Mailchimp is how a business stays in touch with the people who care about it. A
coffee roaster, a nonprofit, a software company: each one keeps a list of
customers, donors, or subscribers, and uses Mailchimp to send that list email
and SMS. Newsletters, product launches, order updates, a discount aimed at
people who haven't bought anything since spring.

The Marketing API is how you do that from code instead of from the Mailchimp
app. You might be building an integration that connects another platform to the
Mailchimp accounts its users already have, running Mailchimp for clients, or
automating your own marketing.

## What people do with Mailchimp

**Collect contacts.** Contacts arrive from signup forms, a storefront, an
import, or an API call. They live in an
[audience](/marketing/concepts/audiences), which is Mailchimp's word for a
list of contacts.

**Organize them.** Sending to the whole audience works, and lots of people do
it. The results are usually better when the message matches who's receiving it,
which is what tags and segments are for. Contacts get labeled with
[tags](/marketing/concepts/audiences/contacts), and
[segments](/marketing/concepts/audiences/segments) group contacts based on
traits and behaviors, like everyone who opened the last three emails, or
customers who bought a specific product.

**Send something.** Mailchimp sends marketing in two basic ways, and what
separates them is who or what starts the send.

* **Campaigns** are sent by a person. A campaign is one message to a chosen set
  of contacts, sent once or scheduled for later: a monthly newsletter, a Black
  Friday announcement.
* **Automations** are messages triggered by events. A welcome email when
  someone joins, a reminder when a shopper leaves items in a cart, a follow-up
  a week after a purchase. You set the trigger once, and Mailchimp sends every
  time it matches.

Automations are often the reason to reach for the API at all, because automation
triggers depend on data and events sent over the API.

**See what happened.** Reports record opens, clicks, unsubscribes, and revenue
per campaign. Engagement is also something you can segment on, so who opened
the last message can decide who gets the next one.

Mailchimp integrates deeply with e-commerce data. Connecting a store adds a
second model alongside the audience: [stores, products, carts, and orders](/marketing/concepts/e-commerce). Purchases and abandoned carts become
the events that trigger automations, orders let reports attribute revenue to
the campaign that earned it, and what someone bought shapes the product
recommendations inside the messages they get next.

## What the API is for

Most work with the Marketing API is some mix of four jobs.

**Sending data in.** Contacts, purchases, and activity from another system land
in an audience, where the rest of Mailchimp can act on them.

**Getting data back.** Campaign and engagement results come out of Mailchimp
and into a database, a dashboard, or a spreadsheet, where they can sit
alongside the rest of what you know about the same people.
[Webhooks](/marketing/api-concepts/webhooks) push changes to you as they
happen; reporting endpoints let you ask.

**Sending messages.** Campaigns can be built, filled with content, and sent
from the API as well as from the Mailchimp app, so a message can be assembled
out of live data and go out the moment that data says it should. Automations
are set up in Mailchimp and triggered by events you report through the API.

**Automating routine work.** Imports can run on a schedule, contacts can
be tagged by rules, and a weekly campaign can build itself from last week's
numbers. Work that used to need someone at a keyboard can run on its own.

## What the Marketing API does not cover

The Marketing API covers campaigns and automations sent to an audience. It has
no endpoints for per-user application email like password resets, receipts, or
shipping confirmations. Those come from
[Mailchimp Transactional](/transactional), a separate product with its own API
and its own docs. If the message is triggered by one person doing one thing and
goes only to them, that's Transactional, not Marketing.

## Where to go next

* [Audiences](/marketing/concepts/audiences) explains contacts, tags, merge fields, and segments, and how they nest.
* [API structure](/marketing/api-concepts/api-structure) covers the root URL and the conventions every endpoint follows.
* [Import and export contacts](/marketing/build/quickstarts/import-and-export-contacts) is a working sync against an existing audience.
* [Send your first API request](/marketing/build/start-developing/send-your-first-api-request) gets you authenticated and calling in a few minutes.