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Diff checker: compare two texts

Paste an old and a new version of any text, code or document to see exactly what changed. Switch between line and word comparison, view the result side by side or inline, ignore case or whitespace, and copy the changes. Both texts are compared in your browser and never uploaded.

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How to use the Diff Checker

  1. 1Paste the original text on the left and the changed text on the right.
  2. 2Choose Lines to compare line by line, or Words for prose and small edits.
  3. 3Pick Side by side or Inline, and turn on Ignore case or Ignore whitespace if you need to.
  4. 4Read the highlighted changes and the counts, then copy the result as a patch.

Frequently asked questions

How does the diff checker find the changes?

It uses the Myers diff algorithm, the same idea behind git diff, to find the smallest set of additions and deletions that turns the first text into the second. Changed lines are then compared word by word.

Are the texts I compare sent anywhere?

No. The comparison runs entirely in your browser, so it's safe for contracts, code and private documents. Nothing is stored or uploaded.

What does Ignore whitespace do?

It treats runs of spaces and tabs as one space and ignores spaces at the start and end of lines, so re-indented code or re-spaced text doesn't show as changed.

Is there a size limit for comparing texts?

Each side can be up to about a million characters. For two very different large texts the tool stops searching after a few thousand changes and shows a simpler, still correct result, with a note.

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