Free Code Diff Viewer

Compare two code files side by side with syntax-highlighted diffs. Supports unified and split view, line numbers, collapsible unchanged sections, patch export, and automatic language detection. Runs entirely in your browser -- no uploads, no server calls.

Original
Modified
Diff Output

Paste or upload code in both panels, then click Compare

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Open source

QTool.io on GitHub

269 free tools. No signup. Open source. Built by Christian Bucher.

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