---
title: "Update a custom field"
method: PUT
path: "/v4/custom_fields/{id}"
tags: ["Custom Fields"]
---

# Update a custom field

`PUT /v4/custom_fields/{id}`

Updates a custom field label (see [Create a custom field](/api-reference/custom-fields/create-a-custom-field) for more information on labels). Note that the key will change but the name remains the same when the label is updated.<br/><br/><strong>Warning: </strong>An update to a custom field will break all of the liquid personalization tags in emails that reference it - e.g. if you update a `Zip_Code` custom field to `Post_Code`, all liquid tags referencing `{{ subscriber.Zip_Code }}` would no longer work and need to be replaced with `{{ subscriber.Post_Code }}`.

## Path parameters

- `id` integer, required

## Request body

- object
  - `label` string, required

## Response `200`

Updates the custom field and returns its details

- object
  - `custom_field` object, required
    - `id` integer, required
    - `name` string, required
    - `key` string, required
    - `label` string, required

## Other responses

- `401` — Returns a 401 if the token and/or account cannot be authenticated
- `404` — Returns a 404 when the provided id does not exist
- `422` — Returns a 422 with an error mesage when one or more of the parameters are invalid

---

[API](https://skmtc.net/kit/apis/kit-api.md) · [All operations](https://skmtc.net/kit/apis/kit-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/kit/kit-api/revisions/0df0c90d12da/schema)