A text diff tool instantly compares two texts side by side, highlighting additions, removals, and unchanged lines. Whether you are reviewing code changes, comparing document versions, or spotting differences between files, this free online text comparison tool gives you instant, accurate results. No signup required.
Try the Free Online Text Diff Tool
How It Works
Step 1: Paste both texts
Enter the original version of your text in the left box and the modified version in the right box. These can be code snippets, documents, configuration files, or any text content you want to compare.
Step 2: Configure options
Optionally enable Ignore whitespace if you only care about meaningful content changes and want to ignore differences in spacing and indentation.
Step 3: Compare and review
Click the Compare button to see a unified diff output. Lines starting with - were removed, lines starting with + were added, and lines starting with two spaces are unchanged.
Real-World Examples
Code Review: Paste the original function on the left and the proposed changes on the right. The diff instantly shows exactly which lines were added, removed, or modified.
Document Versioning: Compare two drafts of a report. The text diff highlights every addition and deletion so you can review changes before publishing.
Config Debugging: Your application stopped working. Compare the working config with the current one to instantly spot the setting that changed.
Collaborative Editing Review (Team Lead): Two teammates edited the same document in parallel and produced conflicting versions. You paste each version into the tool and instantly see the merged set of changes — every line one editor added that the other missed. You reconcile the differences in minutes rather than reading both files line by line.
Log Analysis (Support Engineer): A user reports an error that stopped occurring after an update. You compare yesterday's log excerpt with today's, and the diff immediately shows the new try/catch block and the removed failing line, pinpointing the fix that resolved the issue.
Features
- Line-by-line comparison with clear + and - indicators
- Ignore whitespace option for formatting-agnostic comparison
- Side-by-side input with unified diff output
- 100% private — all processing happens in your browser
- Works with texts of any size
- Free forever with instant results
Use Cases
Developers
Compare code versions, review pull requests, and identify changes between config files.
Writers & Editors
Track changes between document drafts and compare different versions of articles.
QA & Testing
Compare expected vs actual output and document changes between software releases.
Tips & Best Practices
- Use Ignore whitespace for content-only review: When you only care about meaningful changes, enable the Ignore whitespace option. This prevents formatting differences like re-indentation or trailing spaces from flooding the diff with false positives, so you see exactly what changed in substance.
- Compare from the old version to the new: Always place the older text on the left and the newer text on the right. This keeps the + and - convention consistent: minus lines are what was removed and plus lines are what was added, which reads naturally for reviewers.
- Keep diffs small and reviewable: For very large files, split the comparison into logical sections rather than pasting an entire file at once. A focused diff is far easier to scan for mistakes than a massive wall of changes.
- Use diff for configuration debugging: When a service stops working after a config change, paste the last known-good config against the current one. The tool instantly surfaces the exact setting that differs, cutting debugging time dramatically.
- Pair with the Find & Replace tool: After identifying a changed value, use Find & Replace to apply the same correction consistently across other files or documents.
Frequently Asked Questions
Q: How does the text diff tool work?
A: The tool compares two texts line by line. Lines prefixed with - were removed, lines prefixed with + were added, and lines prefixed with two spaces are unchanged.
Q: What does Ignore whitespace do?
A: When enabled, the tool ignores differences in spaces, tabs, and whitespace when comparing lines. Useful when only meaningful content differs.
Q: Can I compare code snippets?
A: Yes. The tool is perfect for comparing code, config files, or any text content. It handles multi-line blocks well.
Q: Is my text data stored on a server?
A: No. All comparison happens in your browser. Your text is never sent to any server.
Q: Is there a size limit?
A: No. You can compare texts of any size, from short paragraphs to thousands of lines.