A segment is a saved filter over your contacts, built from conditions like tags, custom field values, or contact properties. You can use a segment as the audience for a broadcast. Membership is calculated live every time it's used, and marketing consent is always checked again at the moment a broadcast actually sends.
A segment is a set of conditions combined with AND / OR groups, nested a few levels deep. You can filter on:
| Condition | Example |
|---|---|
| Contact property | name, phone number, channel, or when the contact was created |
| Custom field | any field your organization has defined, compared with the operators that fit its type: equals, not equal, contains, greater than or equal, less than or equal, or one of a list |
| Tag | contact has a specific tag |
| Consent | contact has or hasn't opted in to marketing or service messages |
| Recent activity | contact was seen within a recent period |
Only fields your organization can actually filter on are offered. There's no way to filter on another organization's data: a segment only ever runs against your own contacts.
While you build a segment, a count endpoint tells you how many contacts currently match, and a preview lists a sample of them so you can sanity-check the filter before saving. Because a segment is a live question rather than a stored list, that count reflects your contact book right now, not a snapshot from when the segment was created.
When you create a broadcast, choose a segment instead of a list as its audience. A campaign's audience is either a list or a segment, never both at once.
Membership is resolved when the broadcast is enqueued, not when the segment was created or last opened. That has one important consequence: the marketing consent check runs again at that moment, using the same consent gate every broadcast goes through. A contact who matched your filter yesterday but revoked marketing consent since then is skipped, and no message is sent to them. Consent always has the final say over segment membership.
A segment that a campaign has already used as its audience is kept as part of that campaign's record, so you can still see who a past send actually targeted. Deleting a segment that's referenced this way is blocked until it's no longer in use.