Are my texts uploaded to a server?

No. The comparison runs line by line in JavaScript on your own device. Your text never leaves your browser, so it is safe to compare private documents.

How large a text can I compare?

The tool handles typical documents of thousands of lines instantly. For very large inputs it switches to a fast greedy matching mode so your browser never freezes.

What does “Ignore leading/trailing whitespace” do?

It treats lines as equal when they differ only in spaces or tabs at the start or end, so re-indented code or reformatted text does not show up as changed.

Text Diff Checker

Compare two texts line by line and spot every change

Original text

Modified text

Ignore leading/trailing whitespace

Added Removed Unchanged

Enter text in both boxes above to see the differences…

The comparison runs line by line, entirely in your browser. Nothing is sent or stored anywhere.

About this tool

When a document goes through revisions, a contract, an essay, a config file, reading both versions top to bottom to find what changed is slow and error-prone. The JoliTools text diff checker compares your two texts line by line and highlights exactly what was added, removed, or left untouched, the moment you paste them in.

Added lines appear in green and removed lines in red in a familiar unified view, with a live count of added, removed and unchanged lines up top. An optional whitespace-insensitive mode lets you compare meaning rather than formatting, and the swap button flips the comparison direction with one click.

How to use the text diff checker

1Paste the original version of your text into the left box.
2Paste the modified version into the right box.
3Watch the line-by-line diff highlight added (green) and removed (red) lines live.
4Optionally tick “Ignore leading/trailing whitespace” to compare content only.
5Use “Swap texts” to reverse the comparison direction.

Good to know

Unlike server-side diff tools, everything happens locally in your browser with plain JavaScript, no uploads, no accounts, no waiting. Drafts, source code, legal text and private notes stay on your device while you review every difference.