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Compare exact line changes

Edits update instantly. Whitespace and capitalization count.

How to compare two texts and see exactly what changed

Text Diff lines up two versions of a text and reports which lines were added, which were removed, and how many stayed the same. The comparison runs in your own browser using a background worker, so a contract draft, a log excerpt, or a config file is never uploaded. Whitespace and capitalization count as differences, which is what you want when the change you are hunting is a stray space.

Compare two versions in four steps

  1. Paste the original and the changed textPut the earlier version in Original and the newer one in Changed. Each pane shows its line count, and Swap exchanges the two sides if you pasted them the wrong way round.
  2. Run CompareThe diff is an explicit step rather than something that fires on every keystroke, so large inputs do not fight your typing. A progress indicator appears while the worker runs, and you can cancel it.
  3. Read the summary and the changed linesThe result reports additions, removals, and unchanged line counts, and marks each changed line. Long stretches of identical text are collapsed so the differences are not buried in matching lines.
  4. Copy the diff outCopy diff puts the result on your clipboard for a review comment or a ticket. Edit either side afterwards and the result is flagged as stale until you compare again, so you never copy a diff that no longer matches the text.

What people use Text Diff for

  • Review an edit to a document you do not controlPaste the version you were sent next to the version you had, and see the exact lines someone touched instead of trusting a change summary.
  • Spot the one line that broke a configCompare a working config against the current one and find the changed value, including differences that are only whitespace or capitalization.
  • Check a formatted payload against the previous runContinue from Data Formatter with formatted output already loaded and diff it against the earlier response.

Text Diff questions

Is my text uploaded to compare it?
No. The diff runs inside your browser in a background worker. Neither side of the comparison, nor the result, is sent anywhere.
Does it highlight changes inside a line?
No. The comparison is line by line: a modified line shows as one removal plus one addition. That keeps the result predictable on code and configuration files.
Are whitespace and capitalization ignored?
No, they count. Two lines that differ only by a trailing space or a capital letter are reported as changed, because those differences are often exactly the bug.
How large an input can it handle?
Up to 2 MB and 50,000 lines per side, and a comparison that exceeds ten seconds stops and asks you to reduce the input rather than freezing the tab.
Can it produce a patch file or merge the two versions?
No. It reports and copies the differences; it does not write a unified patch and it does not merge. Apply the change in whichever editor owns the file.
Why does it say the result is stale?
Because one of the inputs changed after the last comparison. Run Compare again before copying, so the diff you paste matches the text you have.