---
title: "Get a segment's dependencies"
method: GET
path: "/v1/segments/{segment_id}/used_by"
tags: ["Segments"]
---

# Get a segment's dependencies

`GET /v1/segments/{segment_id}/used_by`

Use this endpoint to find out which automations and newsletters use a segment.

## Response `200`

Returns the IDs of items that reference the segment.

- object
  - `segment_id` integer — The identifier for a segment; used to target a segment in requests.
  - `used_by` object
    - `campaigns` integer[] — The automations that use this segment.
    - `sent_newsletters` integer[] — The newsletters that you've sent that uses this segment.
    - `draft_newsletters` integer[] — The newsletters that are still in a draft state that reference this segment.

## Other responses

- `404` — The `segment_id` does not exist.
- `429` — Your request is over the 10-per-second limit. `Retry-After` tells you how many seconds you must wait before you send the next request.

## Changes

- **2026-09-02** `5da2740beeb5` — 1 info
  - added the media type `application/json` for the response with the status `429`

[Change history](https://skmtc.dev/customer/apis/customer-io-journeys-api-reference/changes/v1/segments/:segment_id/used_by/get.md)

---

[API](https://skmtc.dev/customer/apis/customer-io-journeys-api-reference.md) · [All operations](https://skmtc.dev/customer/apis/customer-io-journeys-api-reference/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/customer/customer-io-journeys-api-reference/revisions/5da2740beeb5/schema)