Yes. All conversion happens in your browser with JavaScript — your data never leaves your device, never touches a server, and is never stored or logged.

Can it handle large CSV files?

Yes. Files up to 10 MB convert smoothly. For very large files (50 MB+), the browser may slow down — but there are no hard limits since processing is local.

What CSV formats does it support?

RFC 4180 standard CSV, plus common variants with tab, semicolon, and pipe delimiters. Quoted fields with embedded newlines and escaped quotes are fully supported. Fields inside quotes preserve their exact content including leading/trailing whitespace.

Does it handle CSV files without headers?

The converter assumes the first row contains column headers. If your CSV has no headers, add a header row manually before converting, or the first data row will become the field names.

CSV to JSON Converter

Convert CSV spreadsheets into structured JSON arrays. Auto-detects delimiters, parses numbers and booleans — ready for your API or application.

Input — Paste your CSV

Output — JSON result

Delimiter: Pretty-print output

🔒 Runs entirely in your browser — your data never leaves this device. How we verify this.

Also try: JSON to CSV XML to JSON JSON to XML CSV to ICS ICS to CSV All Tools

How to Convert CSV to JSON

Paste your CSV data into the input field. The tool accepts CSV with or without a header row. A sample is pre-loaded to show the expected format.
Configure your options. Choose your CSV delimiter — comma is standard, but semicolons (European locales), tabs (TSV files), and pipes are supported. Toggle the header row setting to match your data. By default, we try to detect column types — you can enable strict mode to keep all values as strings.
Click "Convert to JSON". The parser reads each CSV row and produces a clean JSON array of objects. Column headers become object keys; row values become the corresponding values.
Copy or download. Use the Copy button for your clipboard or Download to save as a .json file ready for your application.

Supported CSV Features

Multiple delimiters: comma, semicolon, tab, and pipe — select from the dropdown.
Header row detection: toggle on if your CSV has column names in the first row; off if every row is data.
Type inference: numbers, booleans (true/false), and null values are automatically detected and typed correctly in JSON output. Disable via Strict mode to keep everything as strings.
Quoted fields: CSV cells containing delimiters or line breaks that are properly quoted (RFC 4180) are parsed correctly.
UTF-8 BOM: toggle the BOM option to add the byte order mark that helps Excel and other tools recognize the encoding.

When to Use CSV to JSON

Importing spreadsheets into web apps. Your client sent you an Excel file of data. Export it as CSV, convert to JSON, and feed it straight into your JavaScript application or REST API.
Database seeding. Many database tools (MongoDB, Firebase, PostgreSQL with jsonb) accept JSON natively. Convert your CSV exports to JSON for one-command imports.
API mocking and testing. Maintain your test data in a friendly spreadsheet format (CSV), then convert to JSON payloads for API endpoint testing.
Configuration management. Non-technical teams can manage configuration data in Google Sheets → export CSV → convert to JSON for your application config.

Format Gotchas

Field quoting is fragile. If your CSV has unquoted fields containing the delimiter character, the parser may split incorrectly. Always ensure fields containing commas are double-quoted per RFC 4180.
Empty cells become empty strings. A blank CSV cell produces "" in JSON, not null. Use Strict mode if you want empty strings preserved rather than inferred.
Line breaks in cells. Multi-line CSV fields must be enclosed in double quotes. If a line break appears outside quotes, the parser treats it as a new row.
Excel encoding issues. If your CSV from Excel produces garbled JSON, re-export the CSV as "CSV UTF-8" (not "CSV" which may use a locale-specific encoding).

FAQ

Is my data secure?

Yes. All conversion happens in your browser using JavaScript. Your data never leaves your device — nothing is uploaded to any server. You can verify this by opening your browser's Developer Tools (F12), going to the Network tab, and clicking Convert. You'll see zero network requests.

What's the maximum CSV size I can convert?

There's no hard limit — processing happens in your browser. For best performance we recommend files under 10 MB. Very large CSVs (100,000+ rows) may cause a brief pause in your browser tab.

Does it handle non-ASCII characters?

Yes. UTF-8 is fully supported. If your CSV contains characters from non-Latin scripts (Chinese, Arabic, Hebrew, Cyrillic, etc.), enable the BOM option to ensure Excel and similar tools recognize the encoding correctly.

What if my CSV has inconsistent columns?

The converter processes each row independently. If row 3 has an extra column compared to the header, that extra value still appears in the JSON output with an auto-generated key. For best results, ensure all rows have the same number of columns.

How do I convert JSON back to CSV?

Use our JSON to CSV converter for the reverse direction. It handles nested JSON structures and custom delimiters.