JSON-LD Sanity Checker

What is JSON-LD?

JSON-LD is a way to describe structured data using JSON. Websites often use it to describe organizations, articles, products, software applications, pages, and other things that machines may need to understand.

A small JSON-LD block might look like this:

{
  "@context": "https://schema.org",
  "@type": "SoftwareApplication",
  "name": "Siteimp",
  "url": "https://siteimp.com/"
}

On a web page, JSON-LD is often published inside a script tag:

<script type="application/ld+json">
  {
    "@context": "https://schema.org",
    "@type": "WebSite",
    "name": "Siteimp",
    "url": "https://siteimp.com/"
  }
</script>

That format is useful, but it can be easy to ship a missing comma, duplicate @id, missing @context, or a field that looked obvious at midnight.

What this checker does

This tool is a sanity checker. It is not a full Schema.org validator, not a Google rich results test, and not an SEO promise machine.

It checks practical things:

1. Whether the pasted input contains valid JSON.
2. Whether a pasted script tag contains JSON-LD.
3. Whether the JSON-LD looks like an object, array, or graph.
4. Whether nodes are missing common fields such as @context or @type.
5. Whether graph items look structurally suspicious.
6. Whether common URL fields look empty, relative, or invalid.
7. Whether common structured-data types are missing useful fields.
8. Whether duplicate @id values appear.

The goal is simple: help you catch obvious problems before you publish or inspect the structured data with more specialized tools.

What this checker does not do

This checker does not guarantee that search engines will use your structured data.

It does not fully validate every Schema.org type, property, or Google rich result requirement. Better tools already exist for that job, and those tools change as search engines change.

This tool is deliberately smaller. It answers the first useful question:

Is this JSON-LD valid, readable, and obviously sane enough to inspect further?

Privacy and local input

This page runs in your browser. There is no account, no backend upload, and no server-side storage.

The checker does not fetch your URL, crawl your page, call an API, or send your structured data to hluska.ca. It only checks the text you paste into the box.

If you refresh or close the page, the current input is gone. That is intentional.

Want to test that?

After this page loads, turn off your internet connection and try using the checker. If it still works, that tells you the checking is happening in your browser.

You can also open your browser developer tools, check the Network tab, and then check pasted JSON-LD. You should not see the JSON-LD being uploaded anywhere.

That does not mean every browser tool is safe. It just gives you a practical way to check what this page is doing.

Before sharing structured data

Checking JSON-LD makes structured data easier to inspect. It does not make the data safe to share.

Before sending structured data to another person or company, check for values such as:

• private URLs
• staging URLs
• internal IDs
• customer data
• email addresses
• usernames
• API keys
• access tokens
• file paths
• machine names
• private product names
• unpublished release details

Unless you have strong protections in place, including legal and data sharing documents where needed, you will usually be better off copying only the exact part you need.

JSON, NDJSON, and JSON-LD

If you only need to format a normal JSON object or array, use the JSON Formatter.

If your file has one JSON object per line, use the NDJSON Formatter.

If you are working with structured data for a web page, article, organization, or software application, this JSON-LD Sanity Checker is the better fit.