User Guide
Learn how to compare documents with DiffMate.
How to Compare
Select Files
Choose two files to compare by clicking "Select File" or dragging and dropping. Left is the original, right is the modified version.
Start Comparison
Click the "Compare" button to begin. Comparison happens instantly in your browser with no server upload.
Review Results
View differences in a side-by-side layout with color coding. Green = added, Red = removed, Orange = modified lines.
Edit & Save
Use arrow buttons to copy changes between sides. When done, click "Save Modified File" to download.
Supported File Formats
Plain text files. Automatically detects various encodings including UTF-8 and EUC-KR.
Comma-separated value files. Compares spreadsheet data in text format.
Microsoft Excel files. Converts sheet data to text for comparison.
PDF documents. Extracts text content for comparison.
Advanced Features
Bidirectional Copy
Copy changes left↔right. Click the arrow button on each line, or use "Apply all changes" for bulk operations.
Color-Coded Changes
Green=added, Red=removed, Orange=modified, Gray=moved lines. Instantly identify change types at a glance.
Character-Level Highlighting
Modified lines highlight exactly which characters changed in red. Uses LCS algorithm for precise minimal change detection.
Minimap Navigation
See the distribution of all changes across the document in the right minimap. Click to jump directly to any location.
Useful Tips
Large Files
Files over 10MB can be processed. Since everything runs in your browser, network speed doesn't matter.
Encoding Support
Automatically detects and handles multiple encodings including UTF-8, EUC-KR, UTF-16, and more.
Offline Use
Once the page is loaded, it works without an internet connection. All processing happens in the browser.
Save Files
Download modified files in TXT format after comparison. Original and modified versions can be saved separately.
Security
Files are never uploaded to a server. You can safely compare confidential documents and files containing personal information.