CSV to JSON Converter
Convert CSV to JSON and JSON back to CSV with delimiter and header detection.
Convert CSV to JSON and JSON Back to CSV
CSV is how spreadsheets and databases export data; JSON is how APIs and JavaScript consume it. Moving between them is one of the most common chores in data work, and it is also where data quietly breaks — a comma inside a quoted field, a line break inside a cell, or a leading zero stripped from a postcode.
This converter implements a proper RFC 4180 parser rather than splitting on commas. Quoted fields, escaped quotes and embedded newlines are all handled correctly, and numbers are only converted when doing so is lossless — so "007" stays a string.
Key features
- RFC 4180 compliant parsing — quoted fields, doubled quotes and embedded newlines survive the round trip.
- Both directions — CSV to JSON and JSON to CSV, with the same delimiter settings.
- Multiple delimiters — comma, semicolon, tab and pipe, covering European locales and TSV exports.
- Safe type inference — numbers become numbers only when the value round-trips exactly, protecting IDs and postcodes.
- Header detection — use the first row as keys, or generate column1, column2 automatically.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: CSV to JSON Converter
- Choose a direction
CSV to JSON, or JSON to CSV. The labels and sample data change to match. - Paste your data
Conversion runs as you type, with a summary of rows and columns underneath. - Set the delimiter
Comma is standard, but semicolon is common in locales where the comma is a decimal separator, and tab means a TSV file. - Copy or download
Take the result to your clipboard, or download it as a .json or .csv file.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Converters |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
How are commas inside a field handled?
Correctly. A field containing a comma must be wrapped in double quotes in valid CSV, and the parser respects that. "Smith, John" stays one field rather than splitting into two — the mistake a naive split on commas always makes.
Why did my ID column stay a string?
Deliberately. A value is only converted to a number when the conversion is lossless. "007" would become 7 and lose its leading zeros, so it is kept as text — the same protection applies to long IDs that would lose precision.
Can it handle nested JSON?
CSV is a flat format and cannot represent nesting. When converting JSON to CSV, nested objects and arrays are serialised into the cell as JSON text so no data is lost, but the structure is not expanded into columns.
Is my data uploaded?
No. Parsing and conversion happen entirely in your browser, which is why this is safe for customer lists, exports and anything else you would not paste into a random website.