> For the complete documentation index, see [llms.txt](https://docs.treevox.com/api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.treevox.com/api/error-codes.md).

# Error codes

Treevox uses [HTTP response status codes](https://en.wikipedia.org/wiki/List_of_HTTP_status_codes) to indicate the success or failure of your API requests. If your request fails, Treevox returns an [error](/api/errors.md) using the appropriate status code.

In general, there are three status code ranges you can expect:

* `2xx` success status codes confirm that your request worked as expected
* `4xx` error status codes indicate an error because of the information provided (e.g., a required parameter was omitted)
* `5xx` error status codes are rare and indicate an error with Treevox’s servers

Some `4xx` errors that could be handled programmatically, include an *error code* a short string with a brief explanation as a value for `code`. Below is a list of possible error codes that can be returned.

:white\_check\_mark: `forbidden`

The API key doesn't have permissions to perform the request.

:white\_check\_mark: `api_key_expired`

The API key provided has expired. Obtain your current API keys from the [Dashboard](https://app.treevox.com/my-enterprise/api) and update your integration to use them.

:white\_check\_mark: `contact_email_exist`

The contact email is already registered.

:white\_check\_mark: `contact_not_found`

The contact is not registered.

:white\_check\_mark: `contact_exist`

The contact is already registered