---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/19011#article
headline: "19011: Contact update failed: invalid JSON or non-updatable field"
url: https://www.twilio.com/docs/api/errors/19011
inLanguage: en
dateModified: 2026-04-10T12:20:38.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 19011: Contact update failed: invalid JSON or non-updatable field

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when your contact update request contains invalid JSON or includes fields that this endpoint does not allow you to update. Update only `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, or `custom_fields`.

### Possible causes

* The request body is not valid JSON.
* The request includes one or more fields other than `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, or `custom_fields`.
* The request mixes supported update fields with unsupported fields in the same payload.

### Possible solutions

* Validate the request body and send well-formed JSON.
* Remove any unsupported fields from the update request.
* Limit contact updates to `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, and `custom_fields`.
* Retry the request after you correct the payload.

#### Additional resources

* [Contact API](/docs/messaging/features/contact-api)
* [Compliance Toolkit for Programmable Messaging](/docs/messaging/features/compliance-toolkit)
* [Debugging your Twilio application](/docs/usage/troubleshooting/debugging-your-application)