Is this a character-level or line-level diff?

The viewer shows line-level changes, which is usually what you want for code and config review.

Are my pasted files sent anywhere?

No. Diffing runs entirely in your browser — nothing is uploaded or stored.

Is there a size limit?

There is no fixed limit. Very large files (tens of megabytes) may slow the browser since everything stays in memory.

$diff-checker

Testers

Compare two blocks of text and see the differences highlighted line by line. Added lines in green, removed lines in red. Everything runs in your browser.

Original

Modified

// how-to

How to compare two text blocks

Paste two versions of a file and see a line-by-line diff with additions and removals highlighted.

Paste the original
Drop the original text into the left panel.
Paste the changed version
Drop the updated text into the right panel.
Read the diff
Added lines are green, removed lines are red, and unchanged context stays neutral.
Adjust or share
Tweak either side to explore alternatives, or copy the result to share with a teammate.

// faq

? Is this a character-level or line-level diff?: The viewer shows line-level changes, which is usually what you want for code and config review.
? Are my pasted files sent anywhere?: No. Diffing runs entirely in your browser — nothing is uploaded or stored.
? Is there a size limit?: There is no fixed limit. Very large files (tens of megabytes) may slow the browser since everything stays in memory.