How to update a custom field inside a custom category via API

If you’re updating employee data through the API and the custom field is located inside a custom category, the JSON structure is slightly different from the standard custom field format.

This article explains the correct request structure to use when updating custom category fields through the People endpoint.

Use the following JSON structure when the custom field sits inside a custom category:

{  "custom": {    "category_1773456789123": {      "field_1774567891011": "Example"    }  }}

In this structure:

1. category_1773456789123 represents the custom category ID

2. field_1774567891011 represents the custom field ID

3. "Example" is the value being updated

There’s also an easy way to identify the correct structure for your API body format request:

1. Retrieve the field ID using the “Get all company fields” endpoint

2. Add this ID to either the “people/search” or “people/identifier” endpoints

3. Copy the field structure from the response body

4. Use that same structure in the “Update company employee” endpoint

This method helps ensure the payload structure matches exactly how the field is stored in your account.

For general guidance on updating employee data via API, see the official documentation: How to update custom fields?