Text Diff — Side-by-Side
Compare two texts side-by-side with line and word-level highlighting. 100% client-side — your data never leaves your browser.
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Hello, and welcome to CodeKeet.
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This is a sample paragraph to demonstrate
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the side-by-side text diff feature. It shows
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how changed words and lines are highlighted.
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Some lines stay the same.
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Some lines change.
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That's the point of a diff tool.
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Hello, and welcome to CodeKeet!
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This is a sample paragraph to demonstrate
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the side-by-side text diff feature. It shows
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how changed words and lines get highlighted.
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Added
Removed
Changed line
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🔒 100% private: All diff computation happens in your browser. Your text never leaves your device.
About Text Diff (Side-by-Side)
Comparing two versions of the same text is a daily task for writers, editors, developers, and anyone working with documents. Whether you are comparing a draft against an edit, a config file before and after a change, or two translations of the same sentence, seeing exactly what changed — at the line, word, and character level — makes review fast and accurate. This tool aligns two texts side-by-side and highlights additions, deletions, and modifications. Changed lines get word-level highlighting, so you can spot a single comma or a word swap instantly. It uses the Myers diff algorithm (the same one Git uses internally) and renders everything in your browser.
How It Works
- Paste the original text (left) and the modified text (right).
- The two versions are aligned line-by-line side-by-side.
- Added text is highlighted in green; removed text in red.
- Within changed lines, individual words are highlighted to show exactly what changed.
- Optionally toggle "Ignore case" or "Ignore whitespace" for flexible comparison.
- See the diff stats — added lines, removed lines, unchanged lines.
✨ Key Features
- ✓Line-level alignment (Myers diff algorithm)
- ✓Word and character-level highlighting within changed lines
- ✓Side-by-side columns for easy visual comparison
- ✓Line numbers for both sides
- ✓Ignore case option
- ✓Ignore whitespace option
- ✓Live diff as you type
- ✓Statistics: added, removed, unchanged
- ✓Copy either side or the whole comparison
- ✓100% client-side — no data sent to any server
🎯 Common Use Cases
- →Comparing a draft against an edited version
- →Reviewing changes between two code versions
- →Checking translation differences
- →Comparing config files before and after a change
- →Reviewing document revisions
- →Spotting typos or edits in a manuscript
- →Verifying data cleanup results
- →Comparing two API responses or JSON payloads
💡 Advanced Tips & Pro Insights
- ▸For tiny edits (a word, a comma), word-level highlighting inside changed lines is far more useful than line-level alone. This tool does both.
- ▸Ignore whitespace is helpful for comparing code where indentation differs (tabs vs spaces, 2-space vs 4-space).
- ▸Ignore case is useful when comparing texts that differ only in capitalization — e.g., product names, headings.
- ▸The Myers diff algorithm finds the shortest edit script — the minimum set of insertions and deletions required to transform one text into the other.
- ▸For very large files (10000+ lines), consider a desktop diff tool (Meld, Beyond Compare) or CLI (git diff, diff). This browser tool handles a few thousand lines smoothly.
Frequently Asked Questions
Is this text diff tool free?▾
Yes, this side-by-side text diff is completely free with no signup, email, or usage limits.
Is my data safe?▾
Yes, 100% safe. All comparison happens in your browser. Your text is never sent to any server.
How does it work?▾
The tool uses the Myers diff algorithm — the same one used by Git — to align the two texts line-by-line. Then it performs word-level diff on changed lines to highlight the exact differences.
What is the difference between line-level and word-level diff?▾
Line-level diff marks whole lines as added, removed, or unchanged. Word-level diff highlights individual words that differ within changed lines — much more precise for small edits.
What does "Ignore case" do?▾
When enabled, "Hello" and "hello" are treated as identical. Useful when comparing text where capitalization does not matter.
What does "Ignore whitespace" do?▾
When enabled, differences in spaces, tabs, and blank lines are ignored. Useful for comparing code that was reformatted or files with inconsistent indentation.
Can I compare files instead of pasting?▾
This tool takes pasted text. For file comparison, open each file in a text editor, copy the content, and paste into the two panels.
Does it support very large files?▾
The tool handles a few thousand lines smoothly. For very large files (10k+ lines), use a desktop tool like Meld or the command line (diff, git diff).