---
title: "Lookup a customer's relationships"
method: GET
path: "/v1/customers/{customer_id}/relationships"
tags: ["Customers"]
---

# Lookup a customer's relationships

`GET /v1/customers/{customer_id}/relationships`

Return a list of objects that a person is related to.

You can use the `start` parameter with the `next` property in responses to return pages of results. However, it's possible that you'll see duplicate entries across pages. If you want to export objects or relationships, you may want to use the export feature in our UI to return complete results.

## Response `200`

Returns an array of `cio_relationships`.

- object
  - `cio_relationships` object[] — A list of "objects" that the customer is related to; each JSON object in the array represents an "object" in Customer.io.
    - `object_type_id` integer — The type of object that the customer is related to.
    - `identifiers` object — The `object_id` and `cio_object_id` that a person is related to.
      - `object_id` string — The ID of the object that the customer is related to.
      - `cio_object_id` string — The canonical, immutable identifier for the object that the customer is related to.
    - `attributes` object — Attributes for the relationship between the person and the object.
    - `timestamps` object — Unix timestamps when the object's attributes were last updated.
  - `next` string — Indicates the next page of results. Add `?start=<next_value>` to the request to get the next page of results.

## Other responses

- `404` — The `customer_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/customers/:customer_id/relationships/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.dev/customer/apis/customer-io-journeys-api-reference/revisions/d9edec5f938c?raw)