Diff Checker
Compare two texts side by side with color-coded diff highlighting. All processing happens in your browser.
How to Compare Text
- 1
Enter Original Text
Paste or type the original text in the left textarea.
- 2
Enter Modified Text
Paste or type the modified text in the right textarea.
- 3
Click Compare
View the differences with color-coded highlighting: green for additions, red for removals.
- 4
Review Results
See statistics for lines added, removed, and unchanged. Toggle between line-level and word-level diff.
About Text Diff Comparison
A diff checker compares two pieces of text and highlights exactly what changed between them. This is fundamental for code reviews, configuration management, and version control workflows. Writers compare document drafts, legal teams track contract changes, and QA engineers verify expected versus actual output.
ToolPix's diff checker uses the Longest Common Subsequence (LCS) algorithm — the same approach used by git diff — to identify the minimal set of changes. Lines are color-coded: green for additions, red for removals, gray for unchanged. Statistics summarize total lines added, removed, and unchanged.
Word-level diff provides finer granularity by highlighting individual word changes within modified lines, making it easier to spot a changed variable name, corrected typo, or modified number in dense code blocks. Toggle between line-level and word-level modes as needed.
All comparison happens entirely in your browser — neither the original nor modified text is sent to any server. This makes it safe for comparing sensitive source code, proprietary configurations, and confidential documents. ToolPix's online diff checker is free, unlimited, and requires no registration.
Key Features
Common Use Cases
- •Compare code versions during code review
- •Check configuration file changes before deploying
- •Verify document edits by comparing original and revised versions
- •Debug by comparing expected vs actual output in tests
- •Track changes in contracts, policies, or legal documents
Frequently Asked Questions
What algorithm does the diff checker use?
It uses the Longest Common Subsequence (LCS) algorithm, the same fundamental approach used by git diff and other professional diff tools.
What is the difference between line-level and word-level diff?
Line-level diff marks entire lines as added or removed. Word-level diff highlights specific words that changed within modified lines, providing finer detail for small edits.
Can I compare files instead of text?
Paste the contents of your files into the two text areas. The tool compares text content, not file metadata.
Is there a size limit for the text I can compare?
There is no fixed limit. Very large texts (over 10,000 lines) may take a moment to process depending on your device's performance.
Is my text sent to any server?
No. All comparison happens in your browser. Your text never leaves your device.
Is this diff checker free to use?
Yes. ToolPix's diff checker is completely free with no usage limits, no registration, and no restrictions on text size.
Can I use this on mobile?
Yes. The tool is fully responsive and works on all modern mobile browsers. On smaller screens the side-by-side view adapts for readability.
How does this compare to using git diff?
Git diff works on files within a Git repository and requires command-line access. This online tool lets you compare any two pieces of text instantly — no Git, no terminal, no installation required. It is ideal for quick ad-hoc comparisons.
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