Question 1

Is DiffMate free?

Accepted Answer

Yes, DiffMate is completely free. No registration is required and all features are available without limitations.

Question 2

Are my files uploaded to a server?

Accepted Answer

No, absolutely not. DiffMate runs 100% in your browser. Your files never leave your computer and are never sent to any server. It even works offline once loaded.

Question 3

What file formats are supported?

Accepted Answer

We support TXT, PDF, XLSX (Excel), and CSV. Each format is parsed directly in the browser for text-based comparison.

Question 4

What is the maximum file size?

Accepted Answer

There is no technical file size limit, but since processing relies on browser memory, extremely large files (hundreds of MB) may slow down the browser. Regular documents (under a few dozen MB) work fine.

Question 5

The text looks garbled / encoding issues.

Accepted Answer

DiffMate auto-detects various encodings including UTF-8, EUC-KR (CP949), ISO-8859-1, and UTF-16. If text appears garbled, try converting the file to UTF-8 first.

Question 6

Can I save the comparison results?

Accepted Answer

Yes. Click "Save Modified File A" or "Save Modified File B" below the comparison results to download the current state of each file.

Question 7

Can I compare DOCX (Word) files?

Accepted Answer

DOCX format is not currently supported. Only TXT, PDF, XLSX, and CSV are supported. Please convert DOCX files to TXT or PDF before comparing.

Question 8

Can I revert changes back to the original?

Accepted Answer

Yes. Use the arrow buttons (← →) on each line to copy content between sides. You can also use the "Apply all changes" button to revert everything at once.

Question 9

Does it work on mobile?

Accepted Answer

It works on mobile, but the side-by-side comparison view is best suited for wider screens (PC, tablet).

Question 10

Why are there ads?

Accepted Answer

DiffMate is a completely free service. We use minimal advertising to cover operating costs. Ads do not affect the file comparison functionality.

Question 11

Can I compare multiple sheets in an Excel file?

Accepted Answer

Currently, only the first sheet is compared. To compare a specific sheet, save it as a separate XLSX file first. In Excel, right-click the sheet tab → "Move or Copy" → select "New workbook" to save.

Question 12

Can I compare scanned PDFs?

Accepted Answer

Scanned PDFs (composed of images) cannot be compared because text extraction is not possible. Please add a text layer using an OCR tool like Adobe Acrobat before comparing.

Question 13

Can I use it without an internet connection?

Accepted Answer

Yes, once the DiffMate page is loaded, file comparison works without an internet connection. This is because all processing happens within the browser.

Question 14

What does "moved" mean in comparison results?

Accepted Answer

"Moved" means that a line with the same content exists at a different position in the original and modified files. Lines with the same content but different line numbers are shown in gray.

Question 15

Can I contribute or send feedback?

Accepted Answer

DiffMate is an open-source project. You can submit issues or pull requests on our GitHub repository. Bug reports and improvement suggestions are welcome.

Frequently Asked Questions