# Segments

A segment is a group of contacts. Campaigns send to segments, and automations can start when a contact joins one. Open Contacts › Segments and click New Segment to pick a type. You cannot change the type later.

## Static Segments

You choose the members of a static segment. Add contacts by hand from the contacts list, by CSV import, or through the API with `segment_ids`.

## Dynamic Segments

A dynamic segment holds every contact that matches its conditions. It updates as contacts change. Choose whether a contact must match all of the conditions or any of them, with up to 20 conditions.

> The editor shows a preview of matching contacts and the total before you save.

## Conditions

| Field                                  | Checks                                                                                                                                       |
| -------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
| Email, First name, Last name, Language | is, is not, contains, starts with, ends with, is set                                                                                         |
| Status                                 | is or is not subscribed, pending or unsubscribed                                                                                             |
| Created                                | in the last, not in the last, before, after                                                                                                  |
| Is in segment                          | is or is not in a static segment                                                                                                             |
| Custom properties                      | Checks that fit the property type                                                                                                            |
| Email activity                         | Opened an email, Clicked a link, Got an email, Bounced or Marked as spam, in the last, not in the last, never, or at least a number of times |