---
title: "How it all fits together"
description: "The contacts → segments → campaigns flow and the rules that keep it safe."
url: https://www.unitpost.com/guides/overview
section: Guides
updated: 2026-07-31
---
# How it all fits together

## How it all fits together

> The contacts → segments → campaigns flow and the rules that keep it safe.

Unitpost has two ways to send: the API (transactional mail — receipts, password resets, one-to-one messages triggered by your app) and Campaigns (one-to-many marketing sends to an audience). Most of the dashboard exists to make the campaign path safe and repeatable, and to give you visibility into both.

### The core flow

Three resources form a pipeline, each building on the one before it: Contacts → Segments → Campaigns.

- Contacts are the people you can email — an address plus optional name and custom fields. They carry a marketing subscription state; an unsubscribed or suppressed contact is never mailed.
- Segments are named groups of contacts. A campaign sends to exactly one segment, so a segment is the unit of "who receives this send." Only subscribed members are mailable.
- Campaigns combine a template (the content, authored on the Templates page) with a segment (the audience) and a verified from-domain, then send now or on a schedule.

> **Read the chain bottom-up when something won't send:** A campaign can only send if its template is publishable, its segment has subscribed members, and its from-domain is verified. When a send is blocked, walk back down the chain — domain → segment members → template — and the offending link is almost always one of those three.

### Supporting pieces

- Domains establish sending identity (DKIM/SPF/DMARC). Nothing sends from an address on an unverified domain.
- Templates hold reusable content; the Library stores the images and assets templates reference.
- Emails and Activity are the read side — every individual message and every account event, for debugging and auditing.
- API Keys and Webhooks are the developer surface: keys authenticate the API, webhooks push event notifications back to you.

### Archive, don't delete

Deleting a segment or campaign archives it rather than removing it. Archiving keeps history intact and avoids orphaning references. Archived items are hidden from pickers, can be restored, and are swept ~30 days later once nothing active references them.

> **Active references block destructive actions:** You can't archive a segment that a non-terminal campaign (draft, scheduled, sending) needs — cancel or finish that campaign first. This is a clean, explained stop in both the UI and the API.

Each page has its own guide below. New to the product? Follow the sidebar order: verify a Domain, build a Template, add Contacts, group them into a Segment, then create a Campaign.

## Related

- [Dashboard](https://www.unitpost.com/guides/dashboard): Your account at a glance — sending health, recent activity, and what needs attention.
- [Domains](https://www.unitpost.com/guides/domains): Verify sending domains so your mail authenticates and lands in the inbox.
- [Templates](https://www.unitpost.com/guides/templates): Author reusable email content for campaigns and the API.