Code Diff Checker - Compare Two Files Side by Side Free
Last updated: 2026-03-15
You have two versions of a file and need to see what changed. Maybe you are reviewing a pull request without GitHub, comparing config files between environments, or checking what a colleague modified. A diff tool highlights every addition, deletion, and modification.
Diff View Modes
| Mode | Layout | Best For |
|---|---|---|
| Side by side | Old on left, new on right | Comparing two complete files |
| Inline (unified) | Single column, changes highlighted | Reading changes sequentially |
| Character-level | Highlights individual character changes within lines | Finding subtle changes (typos, variable renames) |
Features
- Syntax highlighting. Supports 50+ programming languages.
- Ignore whitespace. Option to ignore spaces, tabs, and line endings.
- Ignore case. Option for case-insensitive comparison.
- Line numbers. Both original and modified line numbers shown.
- Jump to next change. Navigate between differences quickly.
Common Use Cases
- Code review. Compare before and after versions of code.
- Config comparison. Find differences between staging and production configs.
- Document comparison. Compare two versions of a document or contract.
- Debug. Compare working and broken versions to find the bug.
Compare two files - syntax highlighted, free, instant.
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According to Git documentation, the unified diff format is the standard for representing file differences.
As MDN Web Docs explains, the File API enables browser-based file reading for client-side diff comparison.