CSV ↔ JSON Converter

CSV to JSON Converter Online Free

Free online CSV to JSON and JSON to CSV converter. Parse CSV files, convert JSON arrays. Handles quoted fields and special characters.

Upload a CSV file or paste comma-separated data into the input field, and the converter parses it into a JSON array of objects. Each row becomes an object, with the first row defining the property keys. Quoted fields containing commas or line breaks are handled correctly. For reverse conversion, paste a JSON array and select the JSON to CSV direction to generate a comma-separated spreadsheet. The tool preserves special characters and escapes quotes following RFC 4180 standards. All conversion logic runs locally in your browser.

Data analysts frequently convert CSV exports from databases or spreadsheets into JSON for web applications and API testing. Frontend developers use this when prototyping interfaces that will eventually fetch data from APIs, converting sample CSV datasets into JSON to mock realistic responses. Backend engineers test data transformation pipelines by verifying that their CSV imports match expected JSON structures. Researchers working with survey data export results as CSV from tools like Google Forms, then convert to JSON for custom analysis scripts.

Ensure your CSV has a header row with unique column names, or the JSON output will have duplicate keys that might break parsers. When converting JSON to CSV, flatten nested objects first since CSV is inherently two-dimensional and cannot represent hierarchies. If your CSV contains numeric values that should stay as numbers in JSON, verify the output removes quotes around digits. For large files, test with a small sample first to confirm the conversion handles your specific data format correctly before processing everything.

All processing happens directly in your browser. Your files never leave your device — no server uploads, no cloud storage, no data retention. The tool works offline once loaded, requires no registration, and is completely free with no usage limits.