> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fapost.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Segments

> Selecting contacts by condition, and why the size needs recounting.

A segment is a saved set of conditions over the contact base — "everyone who did
X", rather than a list of names. It is the precise way to choose a
[broadcast](/using/broadcasts) audience.

## The list

Each segment shows its **name**, how many **conditions** it is built from, its
**size**, and when that size was last **counted**.

Three actions sit on every row: **Recount**, **Edit**, **Delete**.

## Size is a snapshot, not a live number

This is the one thing about segments worth understanding, and the *Counted*
column is the clue.

A segment's size is calculated when you ask for it and stored. It does not
update itself as contacts arrive, change, or leave. A segment counted a month ago
shows what it matched a month ago.

**Recount** re-evaluates the conditions against the contact base as it stands
now.

<Warning>
  Recount before using a segment for a broadcast. Sending against a stale count
  is not dangerous in itself — the conditions are re-evaluated when the send
  runs, so the right people are reached either way — but you will be deciding
  whether to send based on a number that no longer describes anything.
</Warning>

## Segments and groups

Both narrow the contact base, and they are not interchangeable:

|                                    |                                                                      |
| ---------------------------------- | -------------------------------------------------------------------- |
| **Segment**                        | A condition. Membership is derived, and changes as contacts do.      |
| **[Group](/using/contact-groups)** | A list. Membership is assigned, and changes when someone changes it. |

Use a segment for "everyone who bought in the last month" — nobody should have to
maintain that. Use a group for "beta testers" — that is a decision, not a
property.

## Empty segments

A size of zero means the conditions currently match nobody. That is a legitimate
state — a segment for "abandoned cart in the last hour" is empty most of the
time — but if you did not expect it, the conditions are usually narrower than
intended rather than the contact base being emptier than expected.