← Home

Diff Checker

Enter two texts above and click "Compare" to see the differences.

About Diff Checker

Privacy

All comparison happens locally in your browser. Your texts are never uploaded to any server.

Frequently Asked Questions

What is a diff checker?
A diff checker is a tool that compares two texts and highlights the differences between them. It shows which lines were added, removed, or modified, making it easy to track changes between document versions.
What's the difference between side-by-side and inline view?
Side-by-side view shows both texts in separate columns, making it easy to compare corresponding lines. Inline view merges both texts into one stream, showing deletions and additions together - similar to unified diff format.
What does "ignore whitespace" do?
When enabled, the comparison ignores differences in spaces, tabs, and extra line breaks. This is useful when you only care about actual content changes and not formatting differences.
Can I compare code files?
Yes! This diff checker works great for comparing code. It preserves whitespace and indentation in the display, and you can optionally ignore whitespace differences to focus on logic changes.
Is my data secure?
Yes, 100% secure. All comparison happens locally in your browser using JavaScript. Your texts are never sent to any server - we literally cannot see your data.

Related Tools

About Text Diff Checker

Compare text online free with FreeToolBox's Diff Checker — paste two versions of any text and instantly see exactly what changed. Added lines are highlighted in green, removed lines in red, and unchanged content is shown in context. This tool is invaluable for developers reviewing code changes without a full IDE, writers comparing document revisions, legal professionals spotting contract modifications, or anyone who needs to quickly verify what's different between two text files or passages.

The diff algorithm runs entirely in your browser using the Myers diff algorithm — no text is sent to any server. Your documents stay completely private. The side-by-side or inline view makes it easy to review changes at a glance. Completely free, no character limit, no account required.

Best use cases for diff checking

When should you use Diff Checker vs other tools?

Use Diff Checker when you need to see what changed between two text versions. If the content needs cleanup before comparing, pair it with JSON Formatter or Markdown Editor.

No-upload workflow: contracts, logs, drafts, and code snippets stay in your browser while you compare revisions.

Frequently Asked Questions

Does it compare character-by-character or line-by-line?

The tool performs line-by-line comparison by default. For each changed line, word-level differences are highlighted within the line so you can pinpoint exactly which words were added or removed, not just which lines changed.

Can I compare code files?

Yes. The diff checker works with any plain text — source code, markdown, HTML, JSON, logs, or prose. It doesn't require any specific file format; just paste the text from both versions.

Can I use this for JSON, YAML, or Markdown revisions too?

Absolutely. It's especially useful for structured text revisions when you want to inspect edits quickly before or after formatting with JSON Formatter, YAML ↔ JSON Converter, or Markdown Editor.

Is there a text size limit?

No artificial limits. Processing happens in your browser so the only constraint is your device's memory. The tool handles large documents (thousands of lines) efficiently.

Is the text I paste kept private?

Absolutely. All processing uses JavaScript running locally in your browser. Your text is never transmitted to any server — it stays entirely on your device.

Feedback
Buy Me a Coffee at ko-fi.com