Diff Checker

Paste an original and a modified version of some text and see exactly which lines were added or removed.

Original

Modified

Diff

Walkthrough

How to use it

Paste the original text into the left pane.
Paste the modified version into the right pane.
The diff below updates live: lines only in the original are marked with a leading -, lines only in the modified version with a leading +.
Unchanged lines are shown without a marker for context.

Use cases

When you'd use this

Reviewing a config file change. Paste the before and after version of a config or environment file to see exactly what changed without opening a full diff tool.

Comparing two drafts of copy. Check what actually changed between two versions of an email, README, or documentation page.

Sanity-checking a find-and-replace. Confirm a bulk text replacement only touched the lines you intended.

FAQ

Common questions

Does it diff word-by-word or line-by-line?

Line-by-line. For most code and config comparisons this is the most readable granularity.

Can it compare two files directly?

Not yet — paste the contents into each pane. File upload isn't planned since it would require reading file contents anyway, which you can just paste.

Is the text sent anywhere for comparison?

No, the diff algorithm runs entirely in JavaScript in your browser.