Paste or open a CSV or TSV file and get clean JSON: an array of objects, an array of arrays, an object keyed by a column or JSON Lines. Everything runs in your browser.
How it works
Open or paste CSV
Paste CSV, open a .csv or .tsv file, load one from a URL or try the sample. The delimiter and encoding are detected automatically.
Choose the JSON shape
Pick array of objects, array of arrays, object keyed by a column or JSON Lines, and decide how numbers, booleans and empty cells are typed.
Download or copy
Download the .json file, copy it, open it in the JSON Viewer, or send it back to JSON to CSV.
Features
Delimiter and quote handling
Commas, semicolons, tabs and pipes are detected from the data. Quoted fields with commas, double quotes and line breaks are read according to RFC 4180.
Type detection
Numbers, true/false and null become JSON types. Values with leading zeros such as 007 and phone numbers stay text, and empty cells become null, an empty string or are left out.
Nested keys
Nest dotted columns turns headers like user.name and tags[0] into nested objects and arrays, the reverse of JSON to CSV.
Encodings and Excel exports
Files with a BOM, UTF-8 and Windows-1252 are recognized; you can also choose the encoding. A decimal comma setting reads 1,5 from European Excel exports.
Large files
Big CSV files are streamed row by row in a background worker instead of being loaded into memory at once.
Limits & privacy
CSV files can be up to 500 MB; large files are streamed. The table preview shows the first 500 rows, while the downloaded JSON contains all rows. Files above 5 MB are converted from the file without loading them into the editor.
Rows with fewer fields are filled with empty values. A quoted field that is never closed is reported. Numbers longer than a JavaScript number can hold are written exactly. See the privacy page.
FAQ
How do I convert CSV to JSON?
Paste the CSV or open the file. The JSON is created as you type; press Download .JSON to save a .json file or Copy to use it elsewhere.
How do I save CSV to a JSON file?
Press Download .JSON. The file is named after your CSV, for example orders.json.
My CSV uses semicolons. Will it work?
Yes. The delimiter is detected automatically, and you can set comma, semicolon, tab or pipe yourself.
Why do some numbers stay strings?
Values with leading zeros, plus signs or spaces, such as 007 or phone numbers, are kept as text so nothing is lost. Turn off Detect numbers and true/false to keep every value as text.
Can I get JSON Lines instead of an array?
Yes. Choose JSON Lines in JSON format to get one object per line, which suits large files and log tools.
Is this CSV to JSON converter online free?
Yes, it is free and needs no account.
Is my CSV uploaded?
No. The file is read and converted in your browser and never leaves your device.