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Diff Checker

Compare two text or code snippets to highlight added, removed, and modified lines in your browser.

Browser onlyYour data never leaves this device.

Runs entirely in your browser. Code, keys, and text never leave this device and are never stored.

Details: Privacy policy

DIFF RESULTS+2 lines-2 lines
1-function greet() {
2- console.log("Hello, world!");
3+function greet(name: string) {
4+ console.log(`Hello, ${name}!`);
5 }

Diff Checker compares two versions of text, programming code, or configuration files to visually highlight exactly what changed between them. Whether reviewing code revisions, proofreading editorial drafts, inspecting JSON API responses, or debugging configuration updates, spotting subtle additions, deletions, and replacements by eye is tedious and prone to errors. This developer utility runs a deterministic line-by-line difference calculation, tagging additions in green and deletions in red. It provides flexible comparison controls, including optional whitespace and casing indifference, side-by-side or unified presentation, and one-click unified diff patch generation. Because all computation runs directly inside your browser memory, proprietary codebases, confidential contracts, and private secrets are never uploaded to any remote server.

How to use Diff Checker

  1. Paste the original text in the left pane and the modified text in the right pane.
  2. Select your comparison settings (ignore whitespace or case sensitivity).
  3. Inspect the highlighted differences or copy the unified diff patch.

What you get

  • Color-coded visual difference view with line numbers.
  • Totals for added, removed, and unchanged lines.
  • Git-compatible unified diff text ready to copy.

When to use Diff Checker

  • Compare code changes before committing or merging Pull Requests.
  • Spot wording and paragraph revisions across document revisions.
  • Audit server configuration files and environment variable definitions.
  • Generate Git-compatible unified diff patches for code reviews.

Frequently asked questions about Diff Checker

How does the diff algorithm calculate line changes?

It uses the standard Longest Common Subsequence (LCS) algorithm to find the minimal sequence of insertions and deletions required to turn the original text into the modified text.

Can I ignore spaces and capitalization?

Yes, checkboxes allow you to ignore trailing/leading whitespace and letter casing, isolating real semantic content changes.

Can I compare proprietary code and API keys safely?

Yes. Everything runs locally in your browser JavaScript environment. Nothing is transmitted over the internet, and no text is logged.

Does it support programming languages like Python, JS, and HTML?

Yes, it works universally with any plain-text source code, including JavaScript, TypeScript, Python, HTML, CSS, JSON, YAML, and Markdown.

Tools related to Diff Checker

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⚡Embed Diff Checker on Your Site & Get Badge↓

Embed this in-browser tool into any blog, documentation, or dashboard. Includes an optional dofollow backlink badge to credit Tools Hub.

Height:
<iframe src="https://salaq.com/embed/developers/diff-checker" title="Diff Checker — Tools Hub" width="100%" height="640" style="border:0;border-radius:12px;overflow:hidden;max-width:100%;" loading="lazy"></iframe>
<p style="font-size:12px;color:#6b7280;margin-top:6px;font-family:system-ui,-apple-system,sans-serif;">Powered by <a href="https://salaq.com/tools/developers/diff-checker" target="_blank" rel="noopener" style="color:#2563eb;text-decoration:underline;">Diff Checker on Tools Hub</a></p>

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