Developer Tools

CSV/JSON Converter

Convert between CSV and JSON instantly. Supports custom delimiters, file upload, data preview, and formula injection protection — all in your browser.

100% local
Runs in your browser
Zero sent
No tracking, no servers
Input CSV
Output JSON 

        

      


      
      

        
        Drop a CSV or JSON file here, or click to browse
        
      


      
      

        
        
        
      


      
      

      
      

        
Data Preview

        

          

        

      


      
      

        
How to use

        
    
          
  1. 
            1
            
    Choose direction — select "CSV to JSON" or "JSON to CSV" using the tabs above.
    
          
    2. 
          
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            2
            
    Paste or upload data — type directly in the input area, or drag-and-drop a file onto the drop zone.
    
          
    3. 
          
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    Configure options — pick a delimiter, toggle auto-detection, and choose whether the first row is a header.
    
          
    4. 
          
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    Copy or download — grab the converted output with one click. Preview the parsed data in the table below.
    
          
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Frequently asked questions

        

          What CSV formats are supported?
          
The tool supports RFC 4180-compliant CSV with custom delimiters (comma, tab, semicolon, pipe). It correctly handles quoted fields, escaped double-quotes, and embedded newlines.

        

        

          Does it handle quoted fields and embedded newlines?
          
Yes. The parser uses a state-machine approach per RFC 4180 that correctly handles quoted fields containing delimiters, double-quotes escaped as "", and embedded newlines within quoted fields.

        

        

          Is my data safe?
          
Yes. All conversion happens 100% in your browser using JavaScript. Your data never leaves your device — nothing is uploaded to any server.

        

        

          What is CSV formula injection protection?
          
When converting JSON to CSV, cells starting with =, +, -, or @ are prefixed with a single quote to prevent spreadsheet applications from interpreting them as formulas. This follows OWASP security guidelines to protect against CSV injection attacks.

        

        

          What JSON formats are supported?
          
The tool accepts JSON arrays of objects (converted to CSV with column headers from object keys) and JSON arrays of arrays (converted to CSV rows directly). Nested objects are serialized as JSON strings in the CSV output.