Code Diff Checker
Compare two versions of code side by side, with line numbers and every added or removed line highlighted.
Paste the original version of your code into the first box and the modified version into the second box, then click Compare. The tool lines up both versions with line numbers and shows them side by side, lines removed from the original are highlighted in red on the left, lines added in the new version are highlighted in green on the right, and unchanged lines appear in both columns.
This is useful for reviewing a code change before committing it, comparing two versions of a config file, or understanding exactly what changed between a working version and a broken one when debugging.
Does this compare line by line or character by character?+
This tool compares line by line. A single character change inside a long line still shows the entire line as removed and re-added.
Does indentation matter?+
Yes, since comparison is exact per line, a line with different indentation or trailing whitespace is treated as a different line.
Is my code sent to a server?+
No. The comparison runs entirely in your browser using JavaScript.
Can I compare very long files?+
Yes, though very large files may take a moment longer since the comparison runs in your browser rather than on a server.