What is it, and why do I need it?

Think of it as a type of token, that allows you, or permits you, to modify files on Sharepoint through an HTTP request.

When you use POST as your method, and need to use Merge in your header, you also need to include a request digest value.

Without it, you’re not authorized to do this action.

What it will look like to use it in a call;

And

To obtain the X-RequestDigest value, you need to make a POST request to the SharePoint REST API endpoint _api/contextinfo.

This endpoint returns a form digest value that you can use in subsequent requests to authenticate and authorize your actions.

Here is how you can do it:

HTTP Method: POST
URI: https://<your-sharepoint-site>/_api/contextinfo
Headers:
  Accept: application/json;odata=verbose

Example Request

POST https://<your-sharepoint-site>/_api/contextinfo
Accept: application/json;odata=verbose

Example Response

{
  "d": {
    "GetContextWebInformation": {
      "FormDigestTimeoutSeconds": 1800,
      "FormDigestValue": "0x123456789ABCDEF...",
      "LibraryVersion": "16.0.0.12345",
      "SiteFullUrl": "https://<your-sharepoint-site>",
      "SupportedSchemaVersions": {
        "results": ["14.0.0.0", "15.0.0.0"]
      },
      "WebFullUrl": "https://<your-sharepoint-site>"
    }
  }
}

The response will include the FormDigestValue which you can use as the X-RequestDigest header in your subsequent requests.

Extracting the FormDigestValue

You need to extract the FormDigestValue from the response. Here is an example of how you can do this in Power Automate:

Send an HTTP Request to SharePoint:

Method: POST
URI: _api/contextinfo
Headers:
  Accept: application/json;odata=verbose

Parse the Response

Use a “Parse JSON” action to parse the response and extract the FormDigestValue.

Use the FormDigestValue

Use the extracted FormDigestValue as the X-RequestDigest header in your subsequent requests. Example in Power Automate

{
  "method": "POST",
  "uri": "_api/contextinfo",
  "headers": {
    "Accept": "application/json;odata=verbose"
  }
}

1. Parse JSON Action:

Schema:

{
  "type": "object",
  "properties": {
    "d": {
      "type": "object",
      "properties": {
        "GetContextWebInformation": {
          "type": "object",
          "properties": {
            "FormDigestValue": {
              "type": "string"
            }
          }
        }
      }
    }
  }
}

Extract FormDigestValue:

Use the following expression to extract the FormDigestValue:

body('HTTP_Request_to_Get_Form_Digest_Value')?['d']?['GetContextWebInformation']?['FormDigestValue']

Use the FormDigestValue in Subsequent Requests:

Set the X-RequestDigest header in your subsequent requests using the extracted FormDigestValue.

By following these steps, you can obtain the X-RequestDigest value and use it in your HTTP requests to SharePoint.