API Reference

List segment contacts

GET /segments/:id/contacts — the contacts that match a segment.

GET/segments/:id/contacts

Returns the contacts in the segment’s audience that match its filter — a live preview of who a campaign to this segment would reach.

Path parameters

segment_idstringrequired

The segment ID.

Query parameters

limitnumberoptional

Number of contacts to retrieve. An integer between 1 and 100. Optional; if omitted, all matching contacts are returned in a single response up to a ceiling of 1,000 — a segment matching 5,000 contacts returns the first 1,000 with has_more: true, so keep walking with after.

afterstringoptional

The contact ID *after* which to retrieve more contacts (for pagination). The ID is not included in the result. Cannot be combined with before.

beforestringoptional

The contact ID *before* which to retrieve more contacts (for pagination). The ID is not included in the result. Cannot be combined with after.

import { Mailblastr } from 'mailblastr';

const mb = new Mailblastr('mb_xxxxxxxxx');

const { data, error } = await mb.segments.contacts('4c1f8b2e-9a2f-4d71-8f0c-2b5d7e6a1c93');
console.log({ data, error });

Response

{
  "object": "list",
  "has_more": false,
  "data": [
    {
      "id": "479e3145-dd0e-4f64-bf48-1d4b6d4cd8f6",
      "email": "ada@gmail.com",
      "first_name": "Ada",
      "last_name": null,
      "unsubscribed": false,
      "created_at": "2026-06-23T10:00:00.000Z"
    }
  ]
}