CSV to JSON converter
Paste or open your file and get the result instantly. We detect the delimiter (comma by default, but also semicolons, tabs, and pipes), respect quotes and line breaks inside cells, and never upload anything.
Drop a .csv, .tsv, .json, or Excel (.xlsx) file onto the field, or use “Open file”. Nothing is uploaded.
Options
Paste a CSV, drop a file, or try an example. The result appears instantly.
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Result
Parts
Preview
How to use it
- Choose what you want to do: CSV to JSON, JSON to CSV, CSV to XML, CSV to Excel, or Split CSV.
- Paste the text or open the file. Excel files (.xlsx) work too, and you can pick the sheet. The delimiter and encoding are detected automatically.
- Adjust the options: first row as header, data types, decimal comma, JSON shape, and indentation. The result updates right away.
- Check the table preview and the warnings: if a row has a different number of columns, we tell you which line it is on.
- Copy the result or download it as .json, .csv, .xml, .xlsx, or a ZIP with the parts.
Frequently asked questions
Does a semicolon-separated CSV convert correctly?
Yes. Excel with a European regional setting saves CSV files with semicolons because the comma is the decimal separator. The delimiter is detected automatically, but you can also choose it by hand (comma, semicolon, tab, or pipe).
How do I convert numbers like 1.234,56?
Turn on “Decimal comma”. With it, 1.234,56 becomes the number 1234.56 in the JSON. Without it, values with a comma stay as text so your data is not changed. Codes with leading zeros, like 00123, always stay as text.
Are line breaks and quotes inside a cell preserved?
Yes. A quoted cell can contain line breaks, the delimiter, and doubled double quotes (“""”). All of it is read and written correctly. If a quote is left unclosed, we tell you which line it starts on.
Why do accented letters look wrong when I open the CSV in Excel?
Excel needs a mark at the start of the file (a UTF-8 BOM) to recognize that it is UTF-8. When converting JSON to CSV, we add it by default. When you open a CSV saved as Windows-1252, we detect it and read it correctly.
What happens to nested objects and lists when going from JSON to CSV?
Nested objects are flattened with dot notation (address.street). Lists can be joined into one cell, spread across columns (tags.0, tags.1), or expanded into one row per item. The columns are the union of all keys in all records.
Is there a size limit?
There is no fixed limit: everything happens in your browser. For large files, we use a background process with a progress bar so the page does not freeze. The practical limit is your device’s memory.
Shapes of JSON made from a CSV
With the first row as the header, each row becomes an object: name,age and Ann,30 give {"name":"Ann","age":30}. You can also get a list of lists or an object indexed by a column, such as id.
Headers with dots
If you turn on “Nest columns with a dot”, the header address.street produces {"address":{"street":"Main St."}}. It is the reverse of flattening a JSON into a CSV.
Delimiters
- Comma: the standard (RFC 4180).
- Semicolon: Excel with a decimal comma.
- Tab: what you get when you copy from a spreadsheet; also .tsv files.
- Pipe: exports from older systems.
Updated on September 29, 2026