What does the Code Diff Checker do?

It compares two texts or code files line by line and highlights added, removed, and unchanged lines in a side-by-side or unified view.

Can I compare two files instead of pasting text?

Yes, each text box has an upload button so you can load a file directly instead of pasting.

What do the ignore whitespace and ignore case options do?

They make the comparison less strict: ignore whitespace skips differences in spaces and tabs, and ignore case treats upper and lower case letters as the same.

Is the Code Diff Checker free?

Yes, it is completely free to use and everything runs in your browser, so your text never leaves your device.

Code Diff Checker

Paste or upload two texts and see exactly which lines were added, removed, or kept the same. Everything runs in your browser, so your code never leaves your device.

Original text Upload file

Modified text Upload file

Ignore whitespace

Ignore case

Unified view Side by side

How to read the comparison

Added — lines present only in the modified text.
Removed — lines present only in the original text.
In the unified view, unchanged lines appear only near changes (3 lines of context), keeping long comparisons easy to scan.
The Copy diff report button copies a plain-text summary with the statistics, ready to paste into a message or ticket.

Code Diff Checker

How to read the comparison

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