Online Text Lab Logo

Difference Checker

Original Text

Tip: Drag & drop a text-based file (TXT, JSON, XML, MD…) into this box.

Changed Text

Tip: Drag & drop a text-based file (TXT, JSON, XML, MD…) into this box.
Comparison Mode:

Highlighted Differences

Added: 41
Removed: 44
Unchanged: 0
This is the original line.
And another line.This is the changed line.
And a new line.
TL;DR — compare text or code instantly

Paste or upload two versions, choose Characters, Words, or Lines, and see differences highlighted. Export or copy results instantly — no uploads, no tracking.

Difference Checker — highlight edits quickly and privately

Whether you’re reviewing code, editing copy, or comparing API responses, spotting the differences matters. This Difference Checker is built to make that task fast, private, and frustration-free. Paste or upload two snippets — an original and a changed version — and the tool will highlight exactly what’s been added, removed, or left unchanged.

You can switch comparison modes to match the job at hand. Use Lines for documents, logs, and long-form text; Words for small edits and copy tweaks; or Characters when precision matters, like code diffs or string edits. A live summary shows you how many characters were added, removed, or unchanged.

For cleaner results, toggle Ignore whitespace, Ignore case, or Trim each line. If you’re working with JSON, enable Pretty JSON for formatting and Sort keys to ignore ordering differences — perfect for API testing and config comparisons. The side-by-side editors accept drag-and-drop files, so you can quickly compare JSON, XML, HTML, CSS, JS/TS, YAML, CSV, Markdown, or plain text logs.

When you’re finished, copy the highlighted diff to your clipboard or download it as a .txt. Accidentally pasted text on the wrong side? Use Swap to flip without re-typing. All processing happens locally in your browser — nothing leaves your device — so it’s safe for sensitive files, source code, or confidential documents.

This makes it more than an online diff viewer: it’s a practical everyday companion for developers pushing commits, writers revising drafts, editors proofreading, and analysts verifying exported data.

Key features

  • Compare by characters, words, or lines
  • Ignore whitespace and case; trim each line
  • Pretty-print JSON and optionally sort keys
  • Upload or drag-and-drop text files per side
  • Highlight additions and deletions with live summary
  • One-click copy and .txt download
  • Swap sides without re-pasting
  • 100% client-side; nothing leaves your device

Tips

  • Use Pretty JSON + Sort keys to ignore ordering noise in API responses.
  • For prose, Lines mode is easiest to scan; switch to Words for fine edits.
  • If changes look larger than expected, enable Ignore whitespace.
  • Normalize spacing with Text Cleaner before comparing tricky files.

Frequently asked questions

Which file types can I compare?
Works with text formats like JSON, XML, HTML, CSS, JS/TS, YAML, CSV, Markdown, and logs. Not suitable for PDFs or images.
Is my text uploaded anywhere?
No. Everything runs locally in your browser.
Why do I see unexpected results?
Your diff depends on options like Ignore whitespace, Ignore case, Trim lines, and Pretty JSON. Adjust them to refine results.
Can I compare large files?
Large files depend on your device memory. For very big files, break them up or use a desktop diff tool.
Does this handle HTML, SQL, or XML?
Yes. They are plain text. Use Lines or Words mode for the clearest comparison.

Related tools

Whether you’re debugging, proofreading, or auditing, this Difference Checker highlights changes clearly so you can focus on what really matters.