Segments

A segment is a saved filter over the team's contacts — it stores a filter expression, not a member list. Membership is evaluated live: a contact that starts matching the filter is in the segment immediately, and the contact count you see is computed at read time.

A segment created without a filter is a manual membership list: you add and remove contacts explicitly (from the dashboard, or via POST /contacts/{id}/segments/{segmentId} and the MCP's add_contact_to_segment). Both kinds are equally valid broadcast targets.

Filters match on contact fields (email, name, subscribe state, creation date) and on custom properties, with operators such as equals, contains, is-set / is-not-set, and date comparisons. Conditions combine with and/or.

Using segments

• Broadcasts — target a segment instead of all contacts. The fan-out resolves membership at send time using the same filter translator as the contact count, so what you preview is what sends.
• Dashboard filtering — the Contacts view can be filtered by segment, and CSV export respects the active segment filter.

API

POST/GET/PATCH/DELETE /segments and GET /segments/{id} (which includes the live contact_count) — see the API reference. Invalid filter expressions are rejected with 422 and never stored.