About DiffViewer

What this site is

DiffViewer compares two versions of something and shows you what changed: text, source code, JSON and YAML, CSV and Excel files, dotenv files, Markdown documents, and images. Each format gets a page built around how that format actually behaves, rather than one generic box that treats a spreadsheet like a paragraph. Start at Text Compare if you are not sure which you need.

The tools are free to use, and there is nothing to sign up for. Open a page, paste or drop two things, read the result, close the tab.

Everything happens on your device

A conventional web tool sends your file to a server, does the work there, and sends back a result. This one does not have that server. The comparison engines are JavaScript that your browser downloads once, along with the page, and then runs locally — usually in a background thread so the interface stays responsive on large inputs.

The practical consequences are easy to check. Load a tool, disconnect from the network, and it keeps working. Watch the network panel in your developer tools while you paste, and nothing goes out carrying what you pasted. The privacy policy sets out the verification steps in order.

How it stays free

Advertising pays for it. There are no accounts, no paid tier, no usage limits held back for subscribers, and no arrangement where your data is the product — since your data never reaches us, it could not be. Ads are served by Google AdSense and are kept out of the comparison panes themselves. What you see and how ads are personalised depends on the consent choice you make, which you can change at any time from ad and cookie choices.

Who builds it

A small independent team, the same one behind HttpStatus.com and TextTools.com. All three sites follow the same idea: single-purpose utilities that load fast, do one job well, and ask for nothing in return except the ad slot on the page.

Telling us when something is wrong

Bug reports are genuinely welcome, especially ones about a comparison that produced the wrong answer. Use the feedback link on this page and include the tool you were on, what you expected, and what you saw instead. Please do not paste confidential material into a report — a small reconstructed example that shows the same behaviour is more useful anyway, and it keeps your real content where it belongs.

Feature requests go the same way. The roadmap named on the category pages — PDF and Word comparison, three-way merge, list comparison — is shaped largely by what people ask for.