Free JSON Validator

Get a definitive answer: is this JSON valid? Paste any JSON and this free validator returns a clear pass/fail verdict — with the exact line and character of the first error when it fails, plus a structural summary when it passes.

Valid JSON

Invalid JSON




  
Private by design. This tool runs 100% in your browser — your code is never uploaded to any server.

  

    
How to Use the JSON Validator

    
    
      
  1. Paste the JSON you want to check.
    2. 
      
  2. Click Validate JSON for an instant verdict.
    3. 
      
  3. Green means valid — plus a summary of type, keys, and depth.
    4. 
      
  4. Red means invalid — read the error position, fix it, and re-validate.
    5. 
    

  

  

    
Features

    
Validation uses the browser’s strict native JSON parser — the same strictness your code will face — so there are no false passes. On failure, the error position is extracted and mapped to a line and column with a caret pointing at the offending character and the surrounding line shown for context. On success you get type, key count, nesting depth, and size.

    
Benefits & Use Cases

    
Developers sanity-check API payloads, config files, and webhook bodies before they cause runtime errors; QA engineers verify fixtures; anyone hand-editing package.json or tsconfig gets instant feedback. Catching a trailing comma here beats debugging a cryptic crash later.

    
Tips

    
The most common failures are trailing commas, single quotes, comments, and unquoted keys — all legal in JavaScript but illegal in JSON. If you need the data reformatted after validating, the JSON formatter is one click away.

  

  

    
Frequently Asked Questions

    
What makes JSON invalid?
Common culprits: trailing commas, single-quoted strings, unquoted property names, comments, missing or mismatched brackets, and control characters inside strings. JSON is stricter than JavaScript object literals.

    
Is JSON with comments valid?
No. Standard JSON forbids comments, even though some tools (like VS Code settings files) use “JSON with Comments”. This validator enforces strict JSON.

    
Can I validate JSON against a schema?
This tool checks syntax only — that the text is well-formed JSON. Checking that the data matches an expected shape (a JSON Schema) is a separate step requiring a schema validator.

    
Why does the error point at the end of the input?
When a bracket or quote is never closed, the parser only realizes at the end of input — so the reported position is where it gave up, while the actual mistake (the unclosed opener) is earlier. Check bracket balance.

    
Is my JSON uploaded anywhere?
No. Validation runs entirely in your browser — your data never leaves your device.

  

  

    
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