---
title: Core concepts
description: Contacts, topics, lists and brands, and how they relate.
---

Four nouns. Learning them in this order will save you re-modelling
later.

## Contact

A person, identified by their email address, unique within your
workspace. A contact carries a name, whatever custom attributes you
define, and their consent and delivery history.

A contact exists once no matter how many of your lists they are on. If
the same address arrives twice, we merge rather than duplicate, using
your workspace's merge policy to decide which value wins when the two
disagree.

## Topic

**What somebody consented to receive.** "Weekly newsletter", "Product
updates", "Event invitations".

This is the concept people skip, and it is the one that matters. An
unsubscribe is almost never "never contact me again" — it is "stop
sending me *this*". Without topics you only have one switch, so a
reader who is tired of your daily digest has no way to say so except to
leave entirely, or to report you as spam, which costs you far more.

Consent lives on the topic. So does the unsubscribe link, by default.

## List

**A grouping you maintain for your own convenience.** "Lagos
customers", "Signed up in 2026", "Attended the launch".

Lists are about segmentation, not permission. A contact being on a list
does not mean they agreed to anything; their topic subscriptions decide
what they may be sent. You can send a campaign to a list, and we will
still only deliver to the people on it who are subscribed to that
campaign's topic.

If you find yourself making a list called "newsletter subscribers", you
want a topic.

## Brand

**Who the mail is from.** A name, a logo, a sender address, a postal
address, and the sending domain underneath it.

A workspace can hold several brands, which is what an agency needs.
Topics belong to a brand, so a recipient's consent is always to a
specific sender rather than to your account in general.

Brands are reviewed before they can send. See [getting
approved](/guide/approval).

## How they fit together

```
Workspace
└── Brand ............... who the mail is from
    ├── Topic ........... what they consented to receive
    │   └── Subscription  one contact's consent to one topic
    └── Campaign ........ one send, to one topic
Contact .................. the person, shared across the workspace
└── List membership ..... your own segmentation
```

The rule worth remembering: **lists decide who you are considering,
topics decide who you may actually send to.**