Text Diff Checker

Compare two text blocks side-by-side or unified line-by-line and highlight additions, deletions, and line modifications in real-time.

100% Private & Secure

Zero Server Uploads

Your files are processed entirely inside your browser tab using WebAssembly & local JavaScript APIs.

Diff Comparison Visualizer
Original (Old)
Modified (New)
1function calculateTotal(items) {
1function calculateTotal(items) {
2 let total = 0;
2 if (!Array.isArray(items)) return 0;
3 for (let i = 0; i < items.length; i++) {
3 return items.reduce((sum, item) => sum + (item.price || 0), 0);
4 total += items[i].price;
5 }
6 return total;
7}
4}

How to use this tool

1

Paste your original text block or source code into the left text box.

2

Paste your modified text block or new code draft into the right text box.

3

Toggle between Side-by-Side or Unified diff view modes to inspect additions and deletions.

4

Review line counts and summary metrics, then copy the diff report or modified text.

Key Features & Benefits

Side-by-Side & Unified Display

Compare documents side-by-side in dual columns or merge them into a single unified diff view with line markers.

Line Addition & Deletion Highlights

Visually inspect added (green), deleted (red), and modified lines with precise original and new line numbers.

100% Client-Side Privacy

Perform confidential comparisons offline. Zero risk of data leaks, network logging, or server storage.

Frequently Asked Questions