TF

Text Tools

Diff Checker: Compare Two Texts Online

Compare two texts side by side or as a unified diff, with word-level highlights and options to ignore case and spacing.

Runs locally in your browser — your input is not uploaded.

Paste two versions of a text — differences are highlighted as you type.

What is this tool?

Paste the original and the changed version of any text — code, contracts, configs, or essays — and see the differences highlighted as you type. Changed lines show exactly which words were edited, and you can switch to a unified view and download a .diff patch.

The comparison uses the Myers diff algorithm — the same approach as git diff — to find the smallest set of line changes, then runs a second word-level diff on each changed line.

Everything is compared in your browser, which makes it safe for private documents and source code.

For structured JSON, the JSON Editor's Compare mode shows changes by key and path instead of by line.

How to use the Diff Checker

  1. Paste the original text on the left and the changed text on the right.
  2. Differences appear immediately: red for removed, green for added, with changed words highlighted.
  3. Optionally ignore case, whitespace, or blank lines, or show only the changed lines.
  4. Switch to Unified view to see a patch, and copy or download it as a .diff file.

Examples

Unified diff

one
two
three  →  one
2
three
@@ -1,3 +1,3 @@
 one
-two
+2
 three

Frequently asked questions

Can I compare two files?

Open each file in a text editor, copy the contents, and paste them into the two boxes. Any plain-text format works: code, CSV, Markdown, logs, and so on.

What does “Ignore whitespace” do?

Lines that differ only in spaces, tabs, or indentation are treated as equal — useful when code was reformatted.

What is a unified diff?

It's the patch format used by git and code review tools: removed lines start with -, added lines with +, and @@ headers show the line numbers of each change.

Is my text uploaded?

No. Both texts stay in your browser and are never sent to a server.

Want more power later?

Premium tools, higher limits, and API access are on the roadmap. V1 stays free and private in your browser.