CSV to JSON Converter

Frequently asked questions

How are CSV columns mapped to JSON?

With the header option on, the first CSV row becomes the keys and every later row becomes an object. With it off, each row is returned as an array of values. Quoted fields and commas inside quotes are parsed correctly. Everything runs in your browser.

What file types can I upload?

You can upload a .csv file, an .xlsx Excel workbook, or an .xls workbook. The tool reads the first sheet and treats it as tabular data before converting to JSON. Plain CSV pastes also work without any upload.

How large a CSV can this handle?

Because conversion runs in your browser there is no server-side limit, but very large files (above a few hundred thousand rows) may slow down or freeze the tab depending on your device. For files that size, consider splitting the CSV first.

What is the difference between header mode and no-header mode?

In header mode the output is an array of objects where each key comes from the first row, making it easy to access fields by name. In no-header mode the output is an array of arrays, which is more compact but requires you to reference columns by index.