Diff Checker
Spot additions and deletions between two blocks of text side by side.
How to use the Diff Checker
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Paste the original text on the left.
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Paste the changed text on the right.
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Review the highlighted differences.
What is a diff checker?
A diff checker compares two versions of text and highlights the differences line by line — additions, deletions and unchanged content. It's invaluable for reviewing edits, comparing config files, checking copy changes or spotting what changed between two versions. This tool computes the diff locally using a longest-common-subsequence algorithm.
Key features
- Line-by-line additions and deletions
- Color-coded, easy-to-scan results
- Summary of added and removed lines
- Private — text is never uploaded
Frequently asked questions
Does it compare line by line or character by character?
It compares line by line, marking each line as added, removed or unchanged.
Can I compare code and config files?
Yes — any plain text works, including code, JSON, logs and prose.
Is my text uploaded?
No. The comparison runs entirely in your browser.