Diff Checker
Compare two texts and see the differences.
About the Diff Checker
The Diff Checker compares two blocks of text side by side and highlights exactly what changed: added lines, removed lines, and modifications. It is the fastest way to review edits between two versions of a document, spot changes in a contract, compare configuration files, or verify what a colleague modified in shared text.
Unlike online diff services that upload your files, this comparison runs entirely in your browser, which makes it safe for sensitive material like legal documents and source code.
How to use it
- Paste the original text into the left box.
- Paste the modified text into the right box.
- The differences are highlighted automatically: additions, deletions, and changed lines.
- Review the highlighted output to see exactly what changed between the two versions.
Frequently asked questions
What kind of differences does it detect?
It performs a line-by-line comparison and highlights added, removed, and modified lines, so structural changes are easy to scan.
Can I compare code with it?
Yes. It works with any plain text, including source code, JSON, XML, configuration files, and CSV data.
Are my documents uploaded?
No. Both texts are compared locally in your browser and are never transmitted to a server.
Is there a size limit?
No fixed limit. Very large files (tens of thousands of lines) may take a moment, but typical documents compare instantly.