---
title: "Update a single custom field"
method: POST
path: "/api/objects/{objectType}"
tags: ["Objects"]
---

# Update a single custom field

`POST /api/objects/{objectType}`

## Request

- Base URL: `https://app.useitem.io`
- URL: `https://app.useitem.io/api/objects/{objectType}`
- Auth: API key in header `x-api-key`

Updates one custom field on an existing object. This is the legacy endpoint —
for updating multiple fields at once, use `PATCH` instead.

## Request body

- object
  - `id` integer: Record ID (required for companies and custom objects)
  - `email` string: Contact email (alternative to `id` for contacts)
  - `fieldName` string, required: Name of the custom field to update
  - `fieldValue` unknown, required

## Response `200`

Field updated

- object
  - `data` ObjectRecord: A flat object containing all fields. System fields (name, email, phone, etc.) and custom fields are merged into a single level — the `custom_fields` JSON column is flattened so every field is a top-level key.
    - `id` integer: Unique record ID
    - `name` string
    - `email` string
    - `created_at` string, date-time
    - `updated_at` string, date-time
  - `message` string

## Other responses

- `400`: Bad request or field not found
- `401`: Invalid or missing API key
- `404`: Object not found

---

[API](https://skmtc.dev/item/apis/item-api.md) - [All operations](https://skmtc.dev/item/apis/item-api/llms.txt) - [OpenAPI document](https://skmtc.dev/item/apis/item-api/revisions/05e6374d3922?raw)