How to Merge Multiple Excel Workbooks Into One File via API

Description and use

PDF4me API merges multiple Excel workbooks into one file, eliminating manual errors and saving time.

Problem

Monthly close requires merging five regional Excel files into a single master workbook, a task that is error‑prone when done manually.

Outcome

The API merges multiple Excel workbooks in the order specified, resolves sheet name conflicts, and returns a single merged file in Base64, reducing manual effort and errors.

Workflow

• 1. Encode each source workbook to Base64.
• 2. Build JSON payload with "mergeFilesToExcelAction", including "documents" array and optional "outputFileName".
• 3. POST to /ApiV2Excel/ExcelMergeFiles with appropriate headers.
• 4. Receive JSON response containing Base64‑encoded merged workbook.
• 5. Decode and write the merged file to disk.
• 6. Verify success flag and handle errors.

Evidence

PDF4me's Excel Merge Files API handles this as a single HTTP call.

Source

The request body, exactly as documented on the Merge Files Excel API page

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The response comes back as JSON with document (the merged workbook, Base64-encoded), fileName, success, and errorMessage.

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If you're not writing a custom integration, the no-code platform versions of this action expose more control than the bare REST contract above

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