Text & Code Diff Checker
+ added
- removed
Diff
What does this diff checker compare?
It compares two blocks of text line by line and shows which lines were added, removed, or stayed the same — the same approach used by version control tools like Git when showing a diff between two versions of a file.
When would I use this?
- Comparing two versions of a config file, script, or document to see exactly what changed.
- Reviewing a colleague's edit before merging it, when you don't have access to a full version control diff.
- Spotting a subtle difference between two similar blocks of text or code.
How it works
The comparison uses a longest common subsequence (LCS) algorithm implemented in JavaScript, running entirely in your browser. Neither text is sent to a server.
Frequently asked questions
A line-based longest common subsequence (LCS) diff, the same general approach used by tools like diff and git diff, comparing the two texts line by line.
Yes, the diff checker works on any text input, including source code, config files, or JSON — it treats each line as a unit for comparison regardless of content.
No, the comparison runs entirely in your browser using JavaScript. Neither text you paste is transmitted anywhere.
Lines only in the left text are marked as removed, lines only in the right text are marked as added, and unchanged lines are shown without highlighting for easy scanning.
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