Diff Checker / Text Compare

The Diff Checker is a text comparison utility designed to analyze differences between two text documents or code files. It highlights additions, deletions, and character-level edits using clear, intuitive color coding. Powered by Google's `diff-match-patch` algorithm running entirely in the browser, it helps you compare document revisions or trace code modifications. Many online diff tools send your pasted text to third-party databases, risking exposure of confidential contracts, essays, or source code. This tool runs 100% locally in your browser, ensuring your inputs never leave your device. [Diff Algorithm and LCS Principles] Text comparison is based on the Longest Common Subsequence (LCS) algorithm. The engine analyzes 'Original Text' and 'Modified Text' to find the maximum overlapping sequence of characters. It aligns the documents using this shared baseline, highlighting added text in green and deleted text in red (with a strikethrough). In addition to line-by-line diffing, it offers character-level comparison to pinpoint typo edits and spacing changes. [Step-by-Step Guide] 1. Paste your original document or code into the left text area ('Original Text'). 2. Paste your revised document or code into the right text area ('Modified Text'). 3. Configure comparison settings at the top (Line-level or Character-level diff). 4. Click 'Compare' to view the differences in Side-by-Side or Inline view options. 5. Review highlighted edits to trace all changes instantly. [Frequently Asked Questions & Precautions] - Q: Can the tool detect space or newline changes? - A: Yes, it highlights exact whitespace differences, tab adjustments, and carriage returns, making it perfect for debugging formatting anomalies. - Q: Is there a text size limit? - A: For huge text payloads (over 5MB), computing the longest common subsequence can take significant CPU cycles. We recommend splitting massive documents into smaller chunks to keep the browser responsive.