---
title: "Update Contact Custom Fields"
method: PUT
path: "/contacts/{contactId}/custom-fields"
tags: ["contacts"]
---

# Update Contact Custom Fields

`PUT /contacts/{contactId}/custom-fields`

Use this endpoint to update multiple custom field values for a contact.
The limit of the Custom Field list to update cannot be greater than 120.
If the custom field type is Text, the maximum lenght of the text is 500 characters.
Any text beyond that limit will be truncated.

This endpoint is rate limited. Use the `RateLimit-*` response headers to check current limits and remaining quota.

## Path parameters

- `contactId` string, uuid, required

## Request body

- ContactCustomFieldsBodyPut
  - `customFields` object[]
    - `id` string, uuid, required — The unique identifier of the AccuLynx custom field item.
    - `fieldType` 'Text' | 'Number' | 'Date' | 'Boolean', required — Specifies the data type (text, number, date, boolean) for the custom field.
    - `values` string[], required

## Response `204`

No Content

## Other responses

- `400` — Bad Request - The server cannot process the request due to a client error. Common causes: - Invalid request format - Missing required fields - Validation errors in the request data
- `401` — Unauthorized - Authentication is required or has failed. Common causes: - Missing API key - Invalid API key - Expired or deactivated API key
- `404` — Not Found - The requested resource does not exist. Common causes: - Invalid subscription ID - Subscription has been deleted - URL path contains typos or incorrect values
- `416` — Range Not Satisfiable - The requested page of results is not available. Common causes: - pageStartIndex is beyond the available data range - Invalid pagination parameters
- `429` — Too Many Requests

---

[API](https://skmtc.net/acculynx/apis/acculynx-api-v2.md) · [All operations](https://skmtc.net/acculynx/apis/acculynx-api-v2/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/acculynx/acculynx-api-v2/versions/3a9e3886e400/schema)