---
title: "Add Field to List"
method: POST
path: "/add-field-to-list.json"
tags: ["Contacts & Lists"]
---

# Add Field to List

`POST /add-field-to-list.json`

Add or update custom fields on an existing list

## Response `200`

Successful response

- object
  - `custom_n` string[] — Custom field names created.
  - `id` integer — ID of the list added to.
  - `error` object
    - `code` string — Error code.
    - `header` integer — HTTP status code.
    - `description` string — Description of the error.

---

[API](https://skmtc.net/kudosity/apis/transmit-sms-api.md) · [All operations](https://skmtc.net/kudosity/apis/transmit-sms-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/kudosity/transmit-sms-api/revisions/9f6c34b849af/schema)