Diff Checker (Side-by-Side & Unified Text Compare)

Compare two blocks of text or source code side-by-side or as a unified diff using an LCS line-matching algorithm with ignore-whitespace and .diff export.

🛡️ 100% Client-Side Privacy Guarantee: This utility executes inside your browser runtime. Zero data is transmitted to external servers.

How to Use Diff Checker (Side-by-Side & Unified Text Compare)

  1. Input your data or choose a sample preset in the interactive workspace.
  2. Click process or calculate to execute instant client-side evaluation.
  3. Copy or export the verified output result with one click.

Compare Code & Text Changes Locally with Unified or Side-by-Side Diff

Paste original and modified text to highlight added, removed, and unchanged lines using Longest Common Subsequence (LCS) alignment. Toggle whitespace normalization, case-insensitive comparison, or download a standard .diff patch file.

Frequently Asked Questions

Is my source code or text uploaded when running a diff?

No. The LCS line diff engine executes 100% client-side in your browser.

Can I download or copy the diff output?

Yes. Use Copy .diff or Save .diff to export the unified line changes.