> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blinkops.com/llms.txt
> Use this file to discover all available pages before exploring further.

# EBS List Changed Blocks

Returns information about the blocks that are different between two Amazon Elastic Block Store snapshots of the same volume/snapshot lineage.

<Note>
  External Documentation

  To learn more, visit the [AWS documentation](https://docs.aws.amazon.com/ebs/latest/APIReference/API_ListChangedBlocks.html).
</Note>

## Basic Parameters

<div className="integrations-table">
  | Parameter          | Description                                                                                                                                                                                                                                                               |
  | ------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  | AWS Region(s)      | Enter the desired AWS Region(s).<br /><br />To execute the action in multiple regions, provide a comma-separated list.<br />For example: `us-east-1,eu-west-2`.<br /><br />If you wish to run the action in all available regions, use the asterisk symbol (`*`) instead. |
  | First Snapshot ID  | The ID of the first snapshot to use for the comparison.<br /><br />Note: the `FirstSnapshotID` parameter must be specified with a `SecondSnapshotId` parameter; otherwise, an error occurs.                                                                               |
  | Second Snapshot ID | The ID of the second snapshot to use for the comparison.<br /><br />Note: the `SecondSnapshotId` parameter must be specified with a `FirstSnapshotID` parameter; otherwise, an error occurs.                                                                              |
</div>

## Advanced Parameters

<div className="integrations-table">
  | Parameter                        | Description                                                                                                                                                                  |
  | -------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  | Disable XML To JSON Auto Convert | When checked, XML responses are not automatically converted into JSON format.                                                                                                |
  | Max Results                      | Pagination limit.                                                                                                                                                            |
  | Next Token                       | Pagination token.                                                                                                                                                            |
  | Starting Block Index             | The block index from which the comparison should start.<br /><br />The list in the response will start from this block index or the next valid block index in the snapshots. |
</div>

## Example Output

```json theme={"dark"}
{
	"BlockSize": 0,
	"ChangedBlocks": [
		{
			"BlockIndex": 0,
			"FirstBlockToken": "^[A-Za-z0-9+/=]+$",
			"SecondBlockToken": "^[A-Za-z0-9+/=]+$"
		}
	],
	"ExpiryTime": "date-time",
	"NextToken": "^[A-Za-z0-9+/=]+$",
	"VolumeSize": 0
}
```

## Workflow Library Example

[Ebs List Changed Blocks with Aws and Send Results Via Email](https://library.blinkops.com/workflows/ebs-list-changed-blocks-with-aws-and-send-results-via-email)

<div className="iframe-wrapper">
  <div className="iframe-media">
    <img src="https://mintcdn.com/blinkops-2/ojHYuDeYX5FWuN8a/img/Icons/play-box.svg?fit=max&auto=format&n=ojHYuDeYX5FWuN8a&q=85&s=b8af968e71438a9499c3223c9bd29fb2" alt="Workflow Library" width="16" height="16" data-path="img/Icons/play-box.svg" />

    Preview this Workflow on desktop
  </div>

  <iframe className="iframe" src="https://library.blinkops.com/workflows/ebs-list-changed-blocks-with-aws-and-send-results-via-email/canvas" />
</div>