CSV to JSON Converter
Convert CSV to JSON and back, all in your browser. Custom delimiters, RFC 4180 quoted-field parsing, automatic type inference, header detection, and live preview. Your data never leaves your device.
Preview
How to Convert CSV to JSON Online
ToolsPix CSV to JSON Converter bridges two of the most common data interchange formats — CSV (Comma-Separated Values) and JSON (JavaScript Object Notation) — directly in your browser. No server upload, no account, no software required. The tool handles the edge cases that trip up naive split-on-comma implementations.
Key features
- Bidirectional — convert CSV → JSON or JSON → CSV with one click
- RFC 4180 compliant — handles quoted fields, embedded delimiters, line breaks inside quotes, and escaped quotes (
"") - Custom delimiters — comma, tab, semicolon, pipe, or any single character
- Type inference — automatically converts
"42"→42,"true"→true, empty strings →null - Header detection — first row used as JSON keys, or fall back to
field_0,field_1, ... - Live preview table — see your parsed data as a grid before copying the JSON
- Smart quoting — JSON → CSV automatically wraps fields containing the delimiter or newlines
Common use cases
- Convert Excel or Google Sheets exports for use in REST APIs
- Transform JSON API responses into CSV for stakeholders who prefer spreadsheets
- Migrate data between databases that use different formats
- Generate test fixtures from spreadsheet data
- Prepare datasets for charting libraries that consume JSON
FAQ
How does CSV to JSON conversion work?
The parser reads CSV input character by character, tracking quote state to correctly handle delimiters and newlines inside quoted fields. The first row becomes JSON object keys (when "Has header" is checked), and each subsequent row becomes one JSON object. With type inference enabled, numeric and boolean strings are converted to proper JSON types.
What delimiters are supported?
Comma, tab, semicolon, and pipe are built-in. The custom field accepts any single character, so you can parse exotic formats. Tab-separated values (TSV) work natively by selecting the tab option. The same delimiter is used in reverse for JSON → CSV output.
Does it handle quoted fields with commas inside?
Yes. The parser is RFC 4180 compliant — fields wrapped in double quotes can contain the delimiter, line breaks, and escaped quotes (a doubled "" represents a literal quote). On the reverse path, JSON → CSV automatically wraps fields containing special characters and escapes internal quotes.
What is type inference?
CSV is purely textual — every cell is a string. With type inference on, the converter detects numeric values (42, 3.14, -1.5e10), booleans (true, false), and nulls (empty string or the literal text null) and emits them as proper JSON types. Disable it if you need every value to remain a quoted string.
Is my data uploaded anywhere?
No. Conversion runs entirely in your browser using vanilla JavaScript. Your CSV and JSON data is never sent to any server, which makes this tool safe for sensitive business data, financial records, or proprietary datasets.