Privacy

Validation stays in your browser

The validator, preview and examples run entirely in your browser. Markup you paste isn't uploaded when you validate it.

Local history

Your last 12 checks are saved in this browser's localStorage so you can reopen them from the History button. They never leave your device.

Clear my history 0 saved checks

When something is sent

• Test a URL: the URL you enter goes to our server, which fetches that page once and returns its JSON-LD. Nothing is stored.
• Explain and fix with AI: the markup and the findings are sent through Vercel AI Gateway to an AI model to write the answer. Don't paste secrets.
• Both are rate-limited by IP address, held briefly in memory only.

Analytics

We use Ahrefs Web Analytics, a cookieless analytics service, to count page views.