Merge document array to PDF


The 'Merge document array to PDF' flow merges up to 1000 documents provided in a JSON array into a single PDF document. 

Please refer to the Supported Document Types articles for a complete list of the different file formats/document types which are supported for conversion.

Example Flows

Please refer to the following article showcasing the 'Merge document array to PDF' action

Power Automate Templates

Default Parameters

The default 'Merge document array to PDF' flow action parameters are detailed below:

  • PDF Filename: The filename to assign to the resulting PDF document (including the file extension).
  • Documents: A JSON array containing a filename and a Base64 encoded string for each document which should be merged.


Documents - JSON Schema 

The JSON provided within the documents parameter should conform to the following schema:

      "fileName": "filename including extension",
    "fileContent": "File content"


Please review the following article if you experience an issue executing the 'Merge document array to PDF' action: Errors processing Document Arrays

Action Count

The final merge operation count is determined using the following calculation:

Merge Action (1) + (No. of Documents Converted to PDF) = Total Operation Count

For example, merging 48 PDF documents;

1 + 0 = 1

For example, merging 48 non-PDF documents which are also converted to PDF before merging:

1 + 48 = 49

For example, merging 612 documents of which 9 are also converted to PDF before merging:

1 + 9 = 10

Creating the JSON Array

Flow provides the actions required to build the JSON array which is required by the 'Documents' parameter. The following example shows how to retrieve documents from a SharePoint folder and dynamically build the array.

1. Utilise the 'Get Files (properties only)' action to retrieve a list of target files


2. Create a new variable which will be utilised to store the JSON we will provide to the 'Documents' parameter.


3. To build the array we will create a loop using the 'Apply to Each' action which will process each item from the SharePoint 'Get Files (properties only)' action. The 'value' variable is passed from the SharePoint 'Get Files (properties only)' result. 


4. Add a 'Get file content using path' action to retrieve the file. 

4.a Site Address: Set as per the site address from step #1

4.a. File Path: Select the 'Folder Path' and 'File name with extension' properties from the SharePoint 'Get Files (properties only)' result.


5. Add an 'Append to array variable' action to add the JSON for the current document to the variable created in step #3.

5a. Add the following JSON to the Append to array variable' actions 'Value' property:

"fileName": ,


5b. Place the cursor as per the image and select the 'FilenameWithExtension' property from the SharePoint 'Get Files (properties only)' result.


5c. Place the cursor as per the image and select the 'File Content' property from the SharePoint 'Get file content using path' result.


5d. Final configuration


The competed JSON value is as follows:

"fileName": @{items('Apply_to_each')?['{FilenameWithExtension}']},
"fileContent": @{body('Get_file_content_using_path')}

6. Add the 'Merge document array to PDF' action underneath the 'Apply to each' action


7. Provide a 'PDF Filename' value, click the 'Switch to input entire array' icon


8. Pass the 'FilesForMerge' variable created in step #2


9. Add a SharePoint 'Create file' action passing the returned filename and 'File Content' return values from the 'Merge document array to PDF' action.



Advanced Parameters

The advanced 'Merge document array to PDF' flow action parameters are detailed below:

  • Remove Markup: Sets whether comments and tracked changes should be removed from the document(s) upon conversion. This option is only executed for Microsoft Office documents.
  • PDF/A Compliant: Sets whether the resulting document should conform to PDF/A format.
  • PDF/A Compliance Level: Sets the required level of PDF/A compliance.
  • Return File: (Advanced) Sets whether the action should return a file or alternatively an operation ID: Flow Action Return Options: File Content vs. Operation ID


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  • 0
    Landon Patterson
    I was trying to follow this tutorial and I get the invaid expression error when I try to use:

    Seems like the @{} is causing the issue. Do you have any guidance on how to fix this error?
  • 0
    Jay Goodison

    Hi Landon,

    We've modified the article, the @{} is added by Flow when you enter an expression, the simple fix is to remove them. You'll see after adding the expression that the actual string added to the JSON is wrapped by @{}

    Thanks for spotting and feeding back.



  • 0
    Matt Simpson

    Flow has a limit of 100mb (ish) for array variables. If the size of my files exceed this is there any other way to use your merge function?

  • 0
    Jay Goodison

    Hi Matt, Power Automate has a message limit of 100MB, you can't use any action at all if the data sent or received exceeds this threshold.

  • 0
    Jose Vidal

    I am using this is in a Power Automate workflow. It was working fine, but a couple of days ago it started returning only corrupted pdf file.

    That is, every time I send it a good pdf file (just one, for testing) it returns another pdf file that is larger (101KB becomes 155KB) and corrupt. The returned file cannot be opened.

    Is this because I am on the free plan? Is merge not working right now?


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