> ## Documentation Index
> Fetch the complete documentation index at: https://help.cloudtalk.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Update a contact

> Updates only the fields you send. Fields you leave out stay unchanged, and `null` clears a field that can be null.

- `phones` and `emails` replace the whole list when sent.
- `customFields` merges by key: keys you send are set, a key sent as `null` is removed, and other keys stay. Two requests that change different keys at the same time both apply.
- Tags change only through [Add tags to a contact](/api-reference/contacts/add-tags-to-a-contact) and [Remove tags from a contact](/api-reference/contacts/remove-tags-from-a-contact). A `tags` field is rejected as an unknown field.
- A lead can become a contact. A contact cannot become a lead.
- When two requests change the same contact at the same time, the last write wins.
- Text fields are cleaned up before their length is checked and they are stored, as on [Create a contact](/api-reference/contacts/create-a-contact): emojis and other characters that take 4 bytes in UTF-8, and control characters such as line breaks and tabs, become a space; repeated whitespace becomes one space; and spaces at the start and end are removed. This applies to `name`, `title`, `company`, `industry`, `website`, `address`, `city`, `state`, `zip` and custom field values, not to emails or phone numbers.

A request that changes nothing returns `200` with the contact and sends no webhook. Otherwise [`contact.updated`](/guides/webhooks/events/contacts#contact-updated) is sent, and CloudTalk exports the change to your active CRM integrations.



## API Specification

The full API specification for this endpoint is available in the [documentation index](https://help.cloudtalk.io/llms.txt).


## Related topics

- [Edit contact](https://help.cloudtalk.io/api-reference/contacts-legacy/edit-contact.md)
- [Manage contacts with the API](https://help.cloudtalk.io/guides/contacts/manage-with-api.md)
- [How to Import Contacts into CloudTalk](https://help.cloudtalk.io/en/articles/2145547-how-to-import-contacts-into-cloudtalk.md)


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