---
title: Decode Base64 fields
description: The decode_base64_field processor specifies a field to base64 decode. To overwrite fields, either rename the target field or use the drop_fields processor...
url: https://www.elastic.co/elastic/docs-builder/docs/3016/reference/fleet/decode_base64_field-processor
products:
  - Elastic Agent
  - Fleet
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Generally available
---

# Decode Base64 fields
The `decode_base64_field` processor specifies a field to base64 decode.
To overwrite fields, either rename the target field or use the `drop_fields` processor to drop the field, and then rename the field.

## Example

In this example, `field1` is decoded in `field2`.
```yaml
  - decode_base64_field:
      field:
        from: "field1"
        to: "field2"
      ignore_missing: false
      fail_on_error: true
```


## Configuration settings

<note>
  Elastic Agent processors execute *before* ingest pipelines, which means that your processor configurations cannot refer to fields that are created by ingest pipelines or Logstash. For more limitations, refer to [What are some limitations of using processors?](/elastic/docs-builder/docs/3016/reference/fleet/agent-processors#limitations)
</note>


| Name             | Required | Default | Description                                                                                                                                                                                              |
|------------------|----------|---------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `field`          | Yes      |         | Contains:* `from: "old-key"`, where `from` is the origin* `to: "new-key"`, where `to` is the target field name                                                                                           |
| `ignore_missing` | No       | `false` | Whether to ignore missing keys. If `true`, missing keys that should be base64 decoded are ignored and no error is logged. If `false`, an error is logged and the behavior of `fail_on_error` is applied. |
| `fail_on_error`  | No       | `true`  | Whether to fail if an error occurs. If `true` and an error occurs, an error is logged and the event is dropped. If `false`, an error is logged, but the event is not modified.                           |

See [Conditions](/elastic/docs-builder/docs/3016/reference/fleet/dynamic-input-configuration#conditions) for a list of supported conditions.