CSV ↔ JSON Converter

About CSV ↔ JSON Converter

Last updated: May 2026

OptiPix CSV ↔ JSON Converter lets you transform data between CSV and JSON formats entirely in your browser. In CSV → JSON mode, paste or upload any CSV file and get a clean JSON array of objects. Configure the delimiter (comma, semicolon, tab, pipe, or custom), toggle whether the first row is treated as a header, choose the quote character, trim whitespace, and enable type inference to automatically detect numbers, booleans, and null values. A live preview table shows the parsed data before it becomes JSON. In JSON → CSV mode, paste a JSON array of objects and get a properly formatted CSV. Nested objects are automatically flattened using dot notation (e.g., address.city becomes a column). Select your preferred output delimiter. Quoted fields containing the delimiter, embedded commas, or newlines are handled correctly per RFC 4180. Upload .csv or .json files directly, copy the output to clipboard, or download as a file. All processing runs client-side - your data never leaves your device.

How It Works

The CSV parser reads the input character-by-character following RFC 4180 rules, handling quoted fields, escaped quotes, and embedded newlines. In JSON mode, each object is flattened recursively using dot-notation keys, then all rows are joined with the selected delimiter and properly quoted where necessary.

Use Cases

• •Convert spreadsheet exports (CSV) into JSON for use in web apps or APIs
• •Transform API JSON responses into CSV for analysis in Excel or Google Sheets
• •Parse data files with different delimiters (semicolons, tabs, pipes)
• •Flatten nested JSON objects into tabular form for reporting
• •Quickly preview and validate CSV structure before importing to a database

You Might Also Like

If you find CSV ↔ JSON Converter useful, check out these related tools: JSON Formatter / Validator, Base64 Text Encoder / Decoder, and URL Encoder / Decoder. All tools run entirely in your browser with no uploads or signups required.