About Free Online Diff Checker & Code Compare Tool — 22 Languages, Merge, Export
The best free diff checker and code comparison tool online. Compare two code snippets, text files, or entire source files side by side with character-level diff highlighting powered by the LCS (Longest Common Subsequence) algorithm. Supports 22 programming languages including JavaScript, TypeScript, Python, Java, C#, Go, Rust, PHP, Ruby, Kotlin, and Swift with automatic language detection. Choose from split (side-by-side), unified, or Monaco (VS Code) diff view modes. Merge changes between versions with per-block accept/reject — accept all left, accept all right, or cherry-pick individual changes. Navigate between differences with keyboard shortcuts (Alt+↑/↓), search within diff results, enable live auto-compare mode, and view the visual minimap for a bird's-eye change overview. Export your diff as a .patch file for Git or as a full HTML report. Whether you need to compare two files online, review pull requests, debug code changes, diff JSON configs, or find what changed between releases — this free diff checker handles it all. No signup, no limits, no cost. A powerful free alternative to DiffChecker, Meld, WinMerge, and Beyond Compare that runs entirely in your browser.
✨ Key Features of Our Free Online Diff Checker & Code Compare Tool — 22 Languages, Merge, Export
- ✓Free diff checker — no signup, no limits
- ✓22 programming languages with auto-detection
- ✓Character-level and word-level diff highlighting (LCS algorithm)
- ✓Split (side-by-side), Unified, and Monaco (VS Code) view modes
- ✓Block-level merge — accept/reject per change with inline merge buttons
- ✓Bulk merge — accept all left or accept all right in one click
- ✓Change navigation with inline Prev/Next and keyboard shortcuts (Alt+↑/↓)
- ✓Search within diff results with match count and highlighting
- ✓Live auto-compare mode (debounced real-time diffing)
- ✓Configurable sidebar with toggles, ignore whitespace/case, precision, layout
- ✓Visual minimap showing change overview at a glance
- ✓HTML diff report export (shareable, styled, branded)
- ✓.patch file export for Git and version control workflows
- ✓One-click sample data for instant demo
- ✓Keyboard shortcuts (Ctrl+Enter, Alt+↑/↓, Ctrl+S, Escape)
- ✓Synchronized scrolling in split view
- ✓File upload with drag & drop support (20+ file types)
- ✓Fullscreen mode for focused, distraction-free comparison
- ✓100% browser-based — your code never leaves your device
- ✓Dark mode support with automatic theme detection
📖 How to Use Free Online Diff Checker & Code Compare Tool — 22 Languages, Merge, Export
Paste or Upload Your Code
Enter your original code in the left panel and the modified version on the right. Use the Upload button, drag & drop files, or click Sample to load a demo. Supports 22 languages with auto-detection.
Configure Diff Options
Choose your language, view mode (Split/Unified/Monaco), and diff precision (word or character level). Toggle options like ignore whitespace, ignore case, syntax highlighting, line numbers, or enable live auto-compare mode in the sidebar.
Compare & Navigate Changes
Click the Compare button (or press Ctrl+Enter) to see highlighted differences. Use the inline Prev/Next buttons or Alt+↑/↓ keyboard shortcuts to jump between changes. Use the search bar to find specific text within the diff.
Merge & Export Results
Accept or reject individual changes using the inline merge buttons per block. Bulk-accept with 'Accept all left' or 'Accept all right'. Export results as .patch files, HTML reports, or copy the merged output directly.
❓ Frequently Asked Questions
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