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Schema Checker

Validate your schema markup in seconds. Paste JSON-LD (or a full HTML page) and this tool will extract application/ld+json, parse it, and flag syntax errors plus common issues like missing @context or @type. Runs fully offline in your browser.

Category: SEO · URL: /tools/schema-checker.html

No network calls. This checks JSON parsing + basic schema.org field sanity (it does not verify Google Rich Results eligibility).



  

    
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            Privacy: runs locally in your browser. No uploads, no tracking scripts.
          

        

      


      
    


    

      
How to use

      
Use it to catch schema markup issues before you push a page live.
  1. Paste your JSON-LD (or full HTML) into the input box.
  2. Click Check schema.
  3. Review the report for parse errors, missing @type/@context, and other warnings.
  4. Optionally enable Show normalized JSON-LD to see what successfully parsed.

      

        Keywords this page targets (natural cluster): schema checker, schema markup checker, json-ld checker, structured data checker, schema validator, schema.org json-ld validator, check json-ld syntax, validate schema markup online, ld+json checker, schema markup tester, structured data validator, schema @context checker, schema @type missing, extract json-ld from html, validate multiple json-ld blocks, schema error checker, schema warnings checker, schema markup audit, schema markup validation tool, json-ld parser
      

      

        Secondary intents covered: Validate that JSON-LD is valid JSON (no trailing commas, broken quotes, etc.), Extract JSON-LD from a pasted HTML page automatically, Confirm each schema node includes @context and @type, Find which block/node is causing a parse or validation issue, Review a compact report of errors and warnings before publishing, Copy a clean validation report to share with a dev/SEO teammate, See a normalized (pretty-printed) version of parsed JSON-LD, Quickly sanity-check multiple schema blocks on one page
      

    


    

      
FAQ

    
What formats does this schema checker support?
It supports JSON-LD directly, or HTML where it will extract <script type="application/ld+json"> blocks.
Does this validate Google Rich Results eligibility?
No. It checks JSON parsing and basic schema field sanity; Google eligibility depends on additional rules and testing tools.
Why do I see “JSON parse error”?
Your JSON-LD isn’t valid JSON (common causes: trailing commas, unescaped quotes, or pasted smart quotes).
Do I need @context and @type on every node?
@type is required per node. @context is usually on the root; nodes inside @graph can inherit it.
Can this handle multiple schema blocks?
Yes. If your HTML has multiple JSON-LD scripts, it parses and reports each block separately.
Is my data sent to a server?
No. Everything runs locally in your browser and the tool does not make network requests.
What does “normalized JSON-LD” mean?
It’s the parsed JSON-LD re-printed in a consistent format so you can quickly inspect what successfully parsed.


    


    
  


  ","expected":"Found 1 JSON-LD block(s)."},{"name":"Missing @type should be error","input":"{\"@context\":\"https://schema.org\",\"name\":\"No Type\"}","expected":"Missing @type."}];

    // The tool JS must attach:
    // - window.feutexReset(): resets UI
    // - window.feutexSelfTest(tests): returns string log (PASS/FAIL)
    // - window.feutexInit(): optional
    (function(){
      const log = document.getElementById('selfTestLog');
      const btn = document.getElementById('selfTestBtn');
      const resetBtn = document.getElementById('resetBtn');
      function setLog(txt){ if(log) log.textContent = txt || ''; }
      btn?.addEventListener('click', async () => {
        try {
          if(typeof window.feutexSelfTest !== 'function') {
            setLog('Self-test missing: window.feutexSelfTest not defined.');
            return;
          }
          const out = await window.feutexSelfTest(FEUTEX_SELF_TESTS);
          setLog(out || 'No self-test output.');
        } catch(e) {
          setLog('Self-test error: ' + (e?.message || e));
        }
      });
      resetBtn?.addEventListener('click', () => {
        try {
          if(typeof window.feutexReset === 'function') window.feutexReset();
          setLog('');
        } catch(e) {
          setLog('Reset error: ' + (e?.message || e));
        }
      });
      try {
        if(typeof window.feutexInit === 'function') window.feutexInit();
      } catch(_e) {}
      document.getElementById('yr').textContent = String(new Date().getFullYear());
    })();
  

  

  ',
        expected: 'Found 1 JSON-LD block(s).'
      },
      {
        name: 'Missing @type should be error',
        input: '{"@context":"https://schema.org","name":"No Type"}',
        expected: 'Missing @type.'
      }
    ];

    let pass = 0;
    const logs = [];
    for (const t of tests) {
      const out = validateText(t.input, { showJson: false, strictContext: true });
      const ok = out.includes(t.expected);
      logs.push((ok ? 'PASS: ' : 'FAIL: ') + t.name + ' (expect contains: ' + JSON.stringify(t.expected) + ')');
      if (!ok) {
        logs.push('--- Output ---\n' + out);
      } else {
        pass++;
      }
    }
    logs.unshift('Self-test: ' + pass + '/' + tests.length + ' passed');
    return logs.join('\n');
  };
})();