opensearch-docs-cn/_data-prepper/pipelines/configuration/processors/lowercase-string.md

---
layout: default
title: lowercase_string
parent: Processors
grand_parent: Pipelines
nav_order: 60
---

# lowercase_string


The `lowercase_string` processor converts a string to its lowercase counterpart 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 options for configuring the `lowercase_string` processor to convert strings to a lowercase format.

Option | Required | Type | Description
:--- | :--- | :--- | :---
with_keys | Yes | List | A list of keys to convert to lowercase.

<!---## Configuration

Content will be added to this section.

## Metrics

Content will be added to this section.--->