Writing & Text

Diff Checker

Paste two versions of a document, essay or code file to see exactly what was added, removed or changed — line by line, with the changed words highlighted.

View

  • Visual comparison

    Additions in green, removals in red, and changed words highlighted. Choose side-by-side or inline view.

  • Smart options

    Ignore differences in spacing, indentation or letter case to focus on the changes that matter.

  • Change summary

    See how many lines were added, removed, modified and left unchanged — handy for code reviews.

Free online diff checker

A diff (short for “difference”) shows the changes between two versions of a text. It's how developers review code on GitHub, and it's just as useful for checking edits to an essay, a contract or a client brief.

How to use it

  1. Paste the original version on the left and the changed version on the right.
  2. Press Compare. Switching views or options updates the result instantly.
  3. Scroll the result panels sideways to read long lines.

Reading the result

  • Added (+, green): lines that only exist in the modified text.
  • Removed (−, red): lines that only exist in the original text.
  • Modified: a line that was replaced — the exact words that changed are highlighted on each side.
  • Unchanged: lines that are the same in both versions.

Options

  • Ignore whitespace: treats lines as equal when they differ only in indentation, trailing spaces or the amount of spacing between words.
  • Ignore case:treats “Hello” and “hello” as the same.
  • Windows (CRLF) and Unix (LF) line endings are always treated as the same.

Common uses

  • Comparing code before and after a refactor or bug fix
  • Reviewing changes to config files, JSON or API responses
  • Checking what a client or teacher changed in your document
  • Comparing two drafts of an essay, proposal or CV

Private by design. Everything runs in your browser — nothing you enter is uploaded or stored by AISeekho.

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