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§ · free tool

Text Diff. Every change, line by line.

Paste two versions of any text and see exactly what changed — additions in green, deletions in red. Unified or side-by-side, with ignore-case and ignore-whitespace options. Runs entirely in your browser; nothing is uploaded.

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A free online tool by Digital Heroes

Runs entirely in your browser — nothing is uploaded anywhere.

A diff you can trust, with no upload

Text Diff compares your two texts line by line using a longest-common-subsequence algorithm — the same core idea behind git diff. Lines only in the original are marked as removed (red); lines only in the changed version are marked as added (green); everything else lines up untouched with its real line numbers on both sides. Toggle Unified for a single stacked column or Side by side for two aligned panes, and switch on ignore-case or ignore-whitespace when trailing spaces or capitalisation shouldn't count as a change. Because the whole comparison runs in your browser, your content never leaves your device — good for code, config, contracts, essays or anything else you'd rather not paste into a server.

§ 02 · what you can do

Everything a diff should do.

  • Compare any two texts line by line — code, config, documents, essays or plain notes — with every change highlighted.
  • Read it your way in a stacked unified view or two aligned side-by-side panes, switchable any time.
  • Spot additions and deletions instantly: green for added lines, red for removed, with real line numbers on both sides.
  • Ignore case or whitespace so capitalisation or trailing spaces don't get flagged as real changes.
  • Swap Original and Changed in one click to reverse the comparison direction and re-run instantly.
  • Private by construction: the diff runs entirely in your browser — nothing is uploaded and it keeps working offline.
§ 03 · how to use it

Four steps, no manual.

  1. Paste your original text into the left box and your changed text into the right box.
  2. Optionally tick Ignore case or Ignore whitespace so those differences are skipped.
  3. Choose Unified or Side by side, then click Compare.
  4. Review the result — green lines were added, red lines were removed — and use Swap to flip the direction.
§ 04 · faq

Frequently asked questions.

Is Text Diff free?
Yes — completely free for everyone. No sign-up, no account and no usage limits.
Is it private? Is my text uploaded anywhere?
No upload, ever. The whole comparison runs in your browser on your own device — your two texts never leave your computer and nothing is sent to a server.
What is the difference between Unified and Side by side?
Unified stacks everything into one column — added lines with a +, removed lines with a − — like a Git patch. Side by side shows the original and changed text in two aligned panes so you can read matching lines across from each other. Both use the same diff underneath.
What do Ignore case and Ignore whitespace do?
Ignore case treats Hello and hello as the same line. Ignore whitespace collapses runs of spaces and tabs and trims the ends, so re-indented or space-padded lines don't count as changes. Both affect only how lines are matched — the original text is still shown exactly as you pasted it.
Does it work offline?
Yes — once the page has loaded, comparing works without a connection because all the logic runs locally in your browser.
Can it compare code or JSON?
Yes. It's a plain-text, line-based diff, so it works on source code, JSON, YAML, config files, Markdown or ordinary prose. It compares whole lines rather than parsing syntax, which keeps it fast and language-agnostic.

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