Text Diff Checker

About the Text Diff Checker

A text diff checker shows the difference between two versions of any text — code, prose, JSON, logs, contracts — by identifying which lines were added, removed, or kept. Instead of reading both documents end-to-end, you see only what changed, which is how engineers review pull requests and editors review revisions. This tool runs fully client-side using a longest-common-subsequence algorithm, so your content never leaves the browser.

Features

• LCS-based line diff — shows real insertions and deletions, not just pairwise changes
• +/− change counts per diff
• CRLF / LF normalized automatically
• Copy unified patch for use in git or code review
• Handles 8,000+ line documents

How it works

1. Paste the original version into the left panel.
2. Paste the modified version into the right panel.
3. Changes are highlighted instantly: green for additions, red for removals, neutral for unchanged lines.
4. Use 'Copy Patch' to grab a unified-diff output for code review or changelogs.

Use cases

• Code review
• Document comparison
• Version control
• Content editing
• Legal contract review