JSON Formatter / Validator

Validate JSON with friendly error messages and format output for readability.
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Validator options
This tool shows a best-effort line/column hint based on the parse error location.
Quick actions
Privacy: runs locally in your browser. No uploads.
Error details
If your JSON is invalid, you’ll see the error message and a line/column hint here.

              

            


          

        


        
        

          

            
Validate JSON with clear errors

            

              A JSON validator helps you catch syntax issues quickly—missing commas, unquoted keys, invalid strings,
              trailing commas, and broken brackets. This tool validates JSON in your browser and gives a clear error message
              with a best-effort line and column hint to help you fix problems fast.
            

            

              Use the formatter after validation to produce consistent indentation for configuration files, API payloads,
              logging output, and documentation.
            

          

        


        

          

            
Common JSON errors

            
    
              
  • Trailing commas (not allowed in strict JSON)
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  • Single quotes instead of double quotes
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  • Unquoted property names (keys must be quoted)
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  • Invalid escape sequences in strings
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  • Mismatched brackets or missing closing braces
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Frequently Asked Questions (FAQ)


            
1. What is the difference between JSON formatter and validator?
Validator checks if JSON is valid. Formatter makes it readable with indentation.

            
2. Does this tool support JSON with comments?
Strict JSON does not allow comments. Use JSONC tools if your environment supports it.

            
3. Why is my JSON invalid even though it looks correct?
Common reasons are trailing commas, unescaped quotes, or invalid characters.

            
4. Can the validator show exact line and column?
Browsers provide a character position; this tool converts it to a best-effort line/column hint.

            
5. Is my JSON uploaded to your server?
No. Everything runs locally in your browser.

            
6. What does “Sort keys” do?
It orders object keys alphabetically to make output stable for diffs and debugging.

            
7. Can I validate very large JSON?
Large JSON can be slow in the browser. For massive payloads, validate server-side.

            
8. Does formatting change the data?
No. Formatting changes whitespace only; data remains identical.

            
9. Can I use this for API debugging?
Yes. Paste API responses to validate and format them quickly.

            
10. Do you store logs of inputs?
No. No storage, no tracking, and no external API calls.

          

        

        

      


      
      

        

          

            
Quick tips

            
If your JSON comes from JS objects, ensure it’s valid JSON (double quotes, no trailing commas).

            
Use “Validate + Format” to get clean output immediately.


            
Common sources

            

              API responses
              Config files
              Webhook payloads
              Logs