CSV-JSON Converter
Convert between CSV and JSON formats. Easily perform format conversions frequently needed for data analysis and API integration in your browser.
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How to Use
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- 1
Enter Data
Enter CSV or JSON data in the input area. The format will be automatically detected.
- 2
Select Conversion Direction
Click the 'Convert to JSON' or 'Convert to CSV' button to perform the conversion.
- 3
Review and Copy Result
Review the conversion result and copy it to the clipboard using the 'Copy' button. You can also swap input and output using the 'Swap' button.
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About CSV-JSON Converter
CSV-JSON Converter instantly transforms tabular data and JSON object arrays between formats in your browser. Paste a CSV export from Excel or Google Sheets and get a properly structured JSON array in seconds, or take a flat JSON API response and convert it to a spreadsheet-ready CSV. The tool automatically detects whether your input is CSV or JSON, so there is no need to manually select the format. Practical options include configurable JSON indentation (2 spaces, 4 spaces, or tabs) and a swap button that reverses input and output for quick round-trip conversions.
Key Features
- Auto-detection (automatically determines input format)
- Bidirectional conversion (CSV→JSON and JSON→CSV)
- Customizable JSON indentation (2 spaces/4 spaces/tabs)
- Detailed error messages (displays problem line numbers)
- Swap feature to switch input and output
Common Use Cases
- Convert Google Sheets or Excel CSV exports to JSON for APIs
- Transform database export CSV into JSON for seeding or migration
- Flatten JSON API responses to CSV for spreadsheet analysis
- Generate JSON test fixtures from CSV sample data
- Prepare CSV data for import into data pipelines or ETL tools
Frequently Asked Questions
Is a header row required for CSV input?
Yes, CSV-to-JSON conversion requires a header row. The first row is used as the keys in the resulting JSON objects. If your CSV has no headers, add a row of column names before converting.
What CSV format is supported?
Standard comma-delimited CSV (RFC 4180). Values containing commas, double quotes, or line breaks must be enclosed in double quotes. Double quotes inside a field are escaped by doubling them (""). Tab-separated (TSV) or semicolon-delimited files are not currently supported — replace the delimiter with commas first.
What JSON format can be converted to CSV?
Only flat object arrays where every object uses the same keys and all values are primitive types (strings, numbers, booleans, or null). Nested objects and arrays within the JSON cannot be converted directly — flatten them first using a tool like jq or custom JavaScript.
How are empty values handled?
Empty fields in CSV become empty strings ("") in JSON. Empty string values in JSON become empty cells in CSV. Null JSON values are also written as empty CSV cells.
Can I paste data directly from Excel?
Excel copies cells as tab-separated values, not comma-separated. To use Excel data, save the file as CSV first (File → Save As → CSV), then copy the contents. Alternatively, Google Sheets lets you download as CSV directly.
Is my input data sent to a server?
No. Conversion runs locally via PapaParse in your browser. You can safely convert files containing personal information, financial records, or other confidential content.
Can I convert large datasets with thousands of rows?
Yes, several thousand rows typically convert without any issues in-browser. For extremely large files (tens of thousands of rows or more), you may notice slower performance due to browser memory limits. In those cases, command-line tools such as csvjson, jq, or Python's pandas library are better suited.