JSON-LD Syntax Checker
A JSON-LD syntax checker finds the mistakes that stop structured data from being read at all. Paste your code, with or without the script tag, and this free tool shows each syntax error with its line and column, plus common problems such as smart quotes, trailing commas, duplicate keys and missing @type. It can also tidy the code.
Paste your JSON-LD or one or more <script type="application/ld+json"> blocks.
Problems Found
| Line | Column | Problem | How to Fix |
|---|
Formatted Code
This checker performs structural JSON parsing and Schema.org vocabulary checks. For official Google feature certification, verify in the Google Rich Results Test.
What is a json-ld syntax checker and when should you use it?
JSON-LD (JavaScript Object Notation for Linked Data) is the industry-standard syntax recommended by Google and W3C for embedding structured data in HTML documents via script tags. If the JSON-LD contains syntactic flaws—such as unescaped quotation marks, trailing commas, misplaced brackets, duplicate keys, or missing required @context definitions—search engine parsers discard the entire structured data block. This diagnostic syntax validator parses your script payloads in real time, pinpoints exact error line and column offsets, and highlights common formatting traps. To inspect markup currently active on any live web page, extract the raw blocks with our Schema Extractor. Then build fully compliant schemas using our purpose-built generators, including the Article Schema Generator, Organization Schema Generator, Product Schema Generator, Local Business Schema Generator, Event Schema Generator, Recipe Schema Generator, Video Schema Generator, FAQ Schema Generator, and audit overall schema coverage with the Schema Property Completeness Checker across our complete collection of Schema Markup Tools.
How do you use it?
- Paste your JSON-LD or script block.
- Press Check.
- Fix each problem, or use "Fix what is safe".
- Format the code and copy it back.
Working on a comprehensive technical audit? Browse all free SEO tools to discover the next step in your workflow, or contact our technical support team if you require a specialized custom utility.
Result interpretation & practical applications
When evaluating the output of the json-ld syntax checker, review the parsed metrics against your specific site architecture. Outputs are formatted for direct implementation into your HTML source, web server configuration, or Google Search Console audit files.
Always inspect generated values for contextual nuance. Automated tools highlight structural patterns, but manual verification confirms that technical directives align with your overarching SEO strategy.
Technical rules and limitations
- 100% Client-Side Processing: Processing occurs in browser memory using native Web APIs.
- Zero Server Storage: Inputs, outputs, and intermediate states are never saved to our database.
- Standards Compliant: Rules adhere to published Google Search Central and W3C web standards.
Google's introduction to structured data and the JSON standard (RFC 8259).
Common mistakes and troubleshooting
- Copying code from a word processor that adds curly quotes.
- Leaving a comma after the last item.
- Writing the same key twice.
- Adding // comments inside the JSON.
No tool can promise how a search engine will crawl, index, or rank your pages. This tool generates and validates code against documented technical specifications; you determine where to deploy it, and you should always test changes on staging environments first. Google publishes extensive guidelines in Search Central on evaluating third-party SEO tools and advice. Learn more about our technical testing standards on our about us page, or explore full site audits on our pricing page.
Related free tools & workflows
Browse all Schema Markup & Structured Data Tools →Technical SEO Audit Workflows
Indexability & Crawling
Redirects & HTTP Headers
Authoritative Technical Documentation & Standards
This tool executes logic aligned with official technical documentation and search engine webmaster standards:
- Google Search Central structured data overview
Google Search Central: Introduction to Structured Data
Primary engineering source and technical documentation.
- IETF RFC 8259 JSON format standard
IETF RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format
Primary engineering source and technical documentation.
JSON-LD Syntax Checker questions
Does it check Google's rules? ↓
No. It checks syntax. Use the Rich Results Test for feature rules.
Can I paste a whole script tag? ↓
Yes, or several of them.
What does "Fix what is safe" change? ↓
Only curly quotes and trailing commas. Every change is listed.
Is this tool free? ↓
Yes. It is completely free to use and requires no registration or subscription.
Does this tool visit my website or store my files? ↓
No. It executes entirely in your local browser runtime. Your inputs and results are never stored or logged on our servers.
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