Text Diff Checker
Compare two texts side by side with highlighted differences. Supports line-by-line and word-by-word diff modes with split and unified view. Download results as a standard .diff patch file. All comparison happens in your browser.
🔒 All text comparison occurs 100% locally in your web browser. No text is ever uploaded.
How to Use Text Diff Checker
- Paste Original Text: Paste or type the original version of your text into the left panel labeled 'Original'.
- Paste Modified Text: Paste or type the new or modified version into the right panel labeled 'Modified'.
- Choose Diff Mode: Select 'Line by Line' for a paragraph or document comparison, or 'Word by Word' for detecting granular changes within sentences.
- Review & Export: Review differences highlighted in green (added) and red (removed). Switch between Split and Unified views, or download the result as a standard .diff patch file.
Frequently Asked Questions
What algorithm does the diff tool use?
The tool uses the LCS (Longest Common Subsequence) algorithm, the same underlying algorithm used by Git, diff, and patch utilities. It finds the minimum set of changes needed to transform the original text into the modified text.
What is the difference between Split and Unified views?
Split view shows original and modified text in two side-by-side panels with synchronized scrolling. Unified view shows both in a single panel with '+' prefixes for added lines and '-' prefixes for removed lines, similar to git diff output.
Can I compare code files?
Yes. The diff tool works on any plain text content including source code, configuration files, JSON, YAML, Markdown, or prose documents.
Is there a character or size limit?
The tool works well for most documents. For very large texts (thousands of lines), a performance note is displayed and an optimized comparison mode is used to keep the browser responsive.