JSON Formatter & Validator

Paste JSON, get a pretty version. Or a clear error.

100% in your browser. Nothing uploaded.

Ready. 

        

      

    


    

      
Format JSON online without upload

      

        Optimize your workflow with our free, privacy-first JSON formatter and validator. Designed for developers, this tool allows you to pretty-print, minify, and validate JSON data directly in your browser without uploading anything to a server. Quickly identify syntax errors and transform messy data into a clean, readable format with customizable indentation. Whether you're debugging an API response or preparing configuration files, our tool ensures your data stays on your device.
      


      
How to use it

      
    
        
  1. Paste raw JSON into the Input pane (or click Sample for a quick test).
    2. 
        
  2. Pick an indent size (2, 4, Tab, or Minify) and press Format.
    3. 
        
  3. Copy the cleaned-up output, download it as a .json file, or read the error message if your input was invalid.
    4. 
      


      
When to use it

      

      
Why use this one

      
    


    
    
    

      
FAQ

      

        Is this JSON formatter safe to use with private data?
        
Yes. Your input is parsed and reformatted by JavaScript running in this tab. There is no upload, no server-side processing, and nothing about what you paste is logged — useful when the JSON contains tokens, customer records, or anything else you would not send to a random tool.

      

      

        Will it tell me where my JSON is broken?
        
Yes. When the parser rejects your input, the status line shows the line and column of the error and the parser's message (Unexpected token, Unterminated string, and so on), so you can jump straight to the offending character.

      

      

        Can I minify JSON with the same tool?
        
Yes. Pick Minify in the indent selector and the output pane shows the smallest valid version of the document — no whitespace, no line breaks — which is what you want before embedding JSON in a URL, query string, or HTTP header.

      

      

        How large a payload can it format?
        
It is limited only by your browser's memory. In practice, anything up to a few megabytes pretty-prints instantly. Very large documents (tens of megabytes) may briefly freeze the tab while the browser parses them, but the work still happens locally.

      

      

        Does it work offline?
        
Yes, once the page has loaded. The formatter is a small static page with no runtime API calls, so it keeps working on a plane, on a locked-down network, or after you disconnect from Wi-Fi.

      

      

        Why is it free?
        
It is a single static page with no backend, so it costs us almost nothing to host. We may eventually run a non-intrusive ad on the page, but the formatter itself stays free and stays client-side.