--- layout: default title: trim_string parent: Processors grand_parent: Pipelines nav_order: 120 --- # trim_string The `trim_string` processor removes whitespace from the beginning and end of a key and is a [mutate string](https://github.com/opensearch-project/data-prepper/tree/main/data-prepper-plugins/mutate-string-processors#mutate-string-processors) processor. The following table describes the option you can use to configure the `trim_string` processor. Option | Required | Type | Description :--- | :--- | :--- | :--- with_keys | Yes | List | A list of keys to trim the whitespace from.