Yes! TxtCmp is 100% free to use with no hidden fees, subscriptions, or premium features. All functionality is available to everyone, forever.

No! All file comparison happens entirely in your browser using JavaScript. Your files never leave your device, and we never see or store your data. This is true client-side privacy.

TxtCmp works with any text-based file:

• Source code: JavaScript, Python, Java, C++, PHP, Ruby, Go, Rust, etc.
• Config files: JSON, YAML, XML, TOML, INI, ENV
• Documents: TXT, CSV, MD, LOG, SQL
• Web: HTML, CSS, SVG

Binary files (images, videos, executables) are not supported.

There are no artificial limits! However, very large files (100MB+) may be slower to process depending on your device's performance. Most files under 10MB work instantly.

Once the page loads, all comparison logic works offline. However, you need an internet connection to initially load the page and its JavaScript libraries.

TxtCmp works on all modern browsers: Chrome, Firefox, Safari, Edge, Opera, and Brave. We recommend keeping your browser updated for best performance.

1. Click "Open Files" or "Paste Text" in the header
2. Upload or drag-and-drop your Original file/text (left)
3. Upload or drag-and-drop your Modified file/text (right)
4. Click "Compare"

The diff view will show all differences with color-coded highlights.

Pro tip: You can also drag files anywhere on the page!

After comparing files, use the "View Mode" buttons in the toolbar:

• Split View: Files side-by-side (default)
• Unified View: GitHub-style single panel with inline changes

Click the line wrap button in the toolbar to toggle line wrapping. This prevents horizontal scrolling for long lines.

Yes! TxtCmp offers multiple export options:

• Markdown: Copy GitHub-style diff to clipboard (Ctrl+Shift+M)
• HTML: Copy standalone HTML page (Ctrl+Shift+H)
• Text file: Download .txt report (Ctrl+D)

All options include statistics and timestamps.

Yes! Use Ctrl+Plus to increase, Ctrl+Minus to decrease, and Ctrl+0 to reset to default (13px).

You can also use the font size buttons in the toolbar. Your preference is saved automatically.

Range: 10px to 24px

Click the "Language" dropdown in the header (next to Recent) to manually select a language.

This is useful when:

• Comparing .txt files that contain code
• Auto-detection fails
• You want to force a specific language

Supported languages: JavaScript, TypeScript, Python, Java, C#, PHP, Ruby, Go, Rust, JSON, YAML, Markdown, Bash, SQL, CSS, HTML, and more (18+ total).

Yes! Click on any stat item at the bottom of the screen:

• Click "X lines added" → view only added lines
• Click "X lines removed" → view only removed lines
• Click "X lines changed" → view only changed lines
• Click "X lines unchanged" → view only unchanged lines

A modal will show the filtered results while keeping the IDE view visible in the background.

File metadata is displayed in the pane headers (split view) after comparison:

• Lines: Total line count
• Characters: Total character count
• Size: File size (B, KB, MB, GB)
• Encoding: Detected encoding (ASCII, UTF-8, etc.)

Hover over each item for more details.

TxtCmp is extremely secure because:

• No server uploads: Files never leave your device
• No data storage: Nothing is saved anywhere
• HTTPS delivery: Encrypted page load
• Client-side only: All processing in your browser

Perfect for sensitive code, confidential documents, and private data.

Only for optional analytics (Google Analytics 4, Microsoft Clarity). No cookies are used for core functionality. You can decline analytics and still use all features.

Nobody! Not even us. Your files are processed entirely in your browser's memory and are never transmitted over the network.

This can happen with very large files (50MB+). Try:

• Closing other browser tabs to free up memory
• Using a faster device or desktop computer
• Splitting large files into smaller chunks

Make sure:

• The file is text-based (not binary)
• Your browser supports the File API (all modern browsers do)
• JavaScript is enabled in your browser

Try refreshing the page or clearing your browser cache. If the problem persists, contact us at hello@justfox.dev.

TxtCmp is built by JustFox, a developer brand by VirtualOx B.V. in the Netherlands. We create privacy-first tools for developers and power users.

Check out our other tools:

• myip.foo - IP address lookup with geolocation
• JustFox - More developer tools coming soon!

Contact us at hello@justfox.dev. We'd love to hear your feedback!