Text Diff Checker
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Compare two pieces of text and see line-by-line additions and deletions, like a Git diff. Highlights every change.
Text Diff Checker
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About This Tool
What is a Diff?
A diff highlights the differences between two versions of a text — the same way Git, GitHub, and code review tools show "what changed". Lines added on the right show in green; lines removed from the left show in red; unchanged lines stay neutral.Use Cases
- Comparing two drafts of an article or contract
- Verifying small code changes side-by-side
- Spotting unauthorized changes in a document
- Tracking edits during proofreading or translation review
- Reviewing exported config or .env files between environments
How It Works
The tool uses the classic Longest Common Subsequence algorithm to find matching lines between the two inputs. Anything not part of the common subsequence is marked as added or removed. The result is similar togit diff but focused on plain text rather than code.Frequently Asked Questions
Does it compare character-level or line-level?
Line-level. Each line is treated as a unit. For more granular character-level diffs (within a single sentence), use a dedicated word-diff tool. Line-level is the standard for comparing documents and configs.
Can it handle large files?
The diff algorithm is O(n×m) in time and memory. Files of a few thousand lines compare instantly. Tens of thousands of lines may take a moment. For very large files, use git diff or a desktop tool like Meld or Beyond Compare.
Why are some 'unchanged' lines marked as added or removed?
If you have similar lines that aren't exactly identical (extra space, different punctuation), the algorithm sees them as separate. Toggle 'Ignore trailing whitespace' to fix the most common cause.