Diff Checker
Developer Tools
Loading tool...
About This Tool
Free, private, serverless text diff checker. Compare two texts side-by-side with line-by-line diff highlighting. Color-coded additions and deletions, line numbers, ignore whitespace and case options. No data leaves your browser — 100% client-side.
How to Use
- Paste your original text in the left panel.
- Paste your modified text in the right panel.
- Optionally enable Ignore whitespace or Ignore case.
- Click Compare to see the diff.
- Review color-coded results: green for additions, red for deletions.
- Use Swap to reverse the panels.
Frequently Asked Questions
How does the diff algorithm work?
The tool uses a Longest Common Subsequence (LCS) algorithm to find the optimal alignment between two texts. It identifies which lines were added, removed, or unchanged with maximum accuracy.
Can I ignore whitespace differences?
Yes! Enable the 'Ignore whitespace' checkbox to treat multiple spaces, tabs, and trailing whitespace as equivalent. This helps focus on meaningful content changes.
What are the use cases?
Code review, document versioning, comparing configuration files, checking translation changes, proofreading drafts, verifying copy-paste accuracy, and tracking text modifications.
Is there a size limit for comparison?
The tool works best with texts up to a few thousand lines. Very large files may take longer to process since the diff algorithm runs entirely in your browser.
Guides & Tutorials
In-depth guides for every tool. Learn how to process your data privately, for free, right in your browser.
Read more