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JSON Validator & Formatter

Free JSON validator and formatter — validate JSON syntax with error highlighting. Free online JSON validation tool.

Validate and format JSON data with error highlighting. Pretty print and minify options. Works 100% in your browser.

JSON Input
Output
Validated JSON will appear here

            

          


          

            Disclaimer: This tool processes all data locally in your browser. No JSON data is sent to any server. Validation is performed using native JavaScript JSON.parse().
          

        

      


      

        
About JSON Validator & Formatter

        
JSON (JavaScript Object Notation) is the de facto standard for data exchange on the web. This free online tool helps you validate JSON syntax and format it for readability. Whether you're debugging API responses, preparing configuration files, or cleaning up data, this validator provides instant feedback with precise error positioning and syntax highlighting.


        
How to Use

        
    
          
  1. Paste your JSON into the input area.
    2. 
          
  2. Click Pretty Print to format with indentation and syntax highlighting.
    3. 
          
  3. Click Minify to compress JSON for transmission or storage.
    4. 
          
  4. If your JSON has errors, the tool will highlight the exact position and describe the issue.
    5. 
          
  5. Use Copy or Download to save your formatted JSON.
    6. 
        


        
Frequently Asked Questions


        

          How does the error position indicator work?
          
When your JSON contains syntax errors, the validator uses JavaScript's native error parsing to extract the exact character position where the error occurred. This helps you quickly locate and fix issues in large JSON files.

        


        

          Is my JSON data kept private?
          
Absolutely. All validation and formatting happens entirely in your browser using JavaScript. No data is ever transmitted to any server, logged, or stored. You can safely use this tool with sensitive API responses or configuration files.

        


        

          What's the difference between Pretty Print and Minify?
          
Pretty Print adds line breaks and indentation to make JSON human-readable, ideal for debugging and editing. Minify removes all whitespace to produce the smallest possible JSON string, perfect for network transmission or storage optimization.

        


        

          What do the syntax highlight colors mean?
          
Keys are shown in cyan, string values in green, numbers in orange, booleans (true/false) in purple, and null values in red. These colors follow popular code editor conventions for quick visual parsing.

        


        

          Does this tool support large JSON files?
          
Yes, the tool can handle JSON files of significant size, limited only by your browser's memory. However, extremely large files (tens of megabytes) may cause performance issues depending on your device.