---
title: Truncate fields
description: The truncate_fields processor truncates a field to a given size. If the size of the field is smaller than the limit, the field is left as is. For example,...
url: https://www.elastic.co/elastic/docs-builder/docs/2395/reference/beats/filebeat/truncate-fields
---

# Truncate fields
The `truncate_fields` processor truncates a field to a given size. If the size of the field is smaller than the limit, the field is left as is.
<definitions>
  <definition term="fields">
    List of fields to truncate. It’s supported to use `@metadata.` prefix for the fields and truncate values in the event metadata instead of event fields.
  </definition>
  <definition term="max_bytes">
    Maximum number of bytes in a field. Mutually exclusive with `max_characters`.
  </definition>
  <definition term="max_characters">
    Maximum number of characters in a field. Mutually exclusive with `max_bytes`.
  </definition>
  <definition term="fail_on_error">
    (Optional) If set to true, in case of an error the changes to the event are reverted, and the original event is returned. If set to `false`, processing continues also if an error happens. Default is `true`.
  </definition>
  <definition term="ignore_missing">
    (Optional) Whether to ignore events that lack the source field. The default is `false`, which will fail processing of an event if a field is missing.
  </definition>
</definitions>

For example, this configuration truncates the field named `message` to 5 characters:
```yaml
processors:
  - truncate_fields:
      fields:
        - message
      max_characters: 5
      fail_on_error: false
      ignore_missing: true
```