The Text Diff tool compares two blocks of text side by side and highlights the differences line by line. Removals from the original text appear in red, additions in the changed text appear in green, and unchanged lines are shown in gray. This makes it easy to spot exactly what was modified between two versions of a document, code file, configuration, or email draft. Whether you are reviewing edits before publishing, comparing configuration files across environments, or checking what changed in a contract, this tool provides clear visual feedback in seconds. All comparison runs entirely in your browser — neither text is ever uploaded to a server, making it safe for confidential and sensitive content.
Enter both texts and click Compare to see the diff.
About Text Diff
Text Diff is a browser-based comparison tool that performs a line-by-line diff between two text inputs. Lines present only in the original appear in red (removed), lines present only in the changed version appear in green (added), and lines that are identical in both appear in gray (unchanged). This visual approach makes it simple to understand what changed at a glance.
The tool is useful for comparing drafts of articles, contract revisions, code snippets, configuration files, or any text where you need to identify modifications. Since the comparison engine runs entirely in JavaScript within your browser, your documents are never transmitted over the network, ensuring complete privacy for sensitive content.
How to Use Text Diff
- Paste the Original (old text) into the first text area — this is the older or baseline version.
- Paste the Changed (new text) into the second text area — this is the newer or modified version.
- Click Compare to generate the diff. Differences appear below with color-coded highlighting.
- Use Clear all to reset both text areas and start a new comparison.
Key Features
- Line-by-line comparison — Clearly shows added, removed, and unchanged lines
- Color-coded output — Red for removals, green for additions, gray for unchanged
- 100% client-side — No server uploads; your texts stay private in your browser
- Handles large texts — Works with documents of any length
- One-click clear — Reset both inputs instantly to start a new comparison
When to Use This Tool
- Comparing two drafts of an article, contract, or email before sending
- Spotting changes between two code snippets or configuration files
- Reviewing edits before accepting or rejecting changes in a document
- Quick "before vs after" check without setting up version control
- Comparing API responses or log outputs from different runs
Technical Details
The comparison is performed line by line using a diff algorithm implemented in JavaScript. Each line from both inputs is compared to determine whether it was added, removed, or left unchanged. The algorithm produces a minimal set of changes. Note that this is a line-level diff — it does not highlight character-level or word-level differences within a line. For character-level diffs, consider using a dedicated code editor or git diff --word-diff. The tool handles texts of any size, though very large documents may take a moment to process.
Conclusion
Text Diff is a fast, private way to compare two versions of any text directly in your browser. With clear color-coded output and zero server communication, it is ideal for reviewing document edits, comparing code, or verifying configuration changes. For related text tools, try Find & Replace or Remove Duplicate Lines.