CSV โ JSON converter
Turn a spreadsheet export into JSON, or an API response into CSV. Handles quotes, line breaks and custom delimiters.
= + - @ get a leading ' so Excel and Sheets cannot run them as formulas (CSV injection).CSV and JSON in practice
CSV is the language of spreadsheets and database exports; JSON is the language of APIs. Moving data between them is a daily chore, and the details (quoted commas, embedded line breaks, byte-order marks) are where hand-written scripts break.
Conversion happens in your browser, so confidential exports never leave your machine. For a typed Java model of the result, feed the JSON to the JSON to Java converter.
Frequently asked questions
How are commas and quotes inside fields handled?
Fields containing the delimiter, a quote or a line break are wrapped in double quotes, and a quote inside a field is doubled (""), as defined in RFC 4180. The parser and the writer both follow it.
What does "detect types" do?
Numbers, true/false and empty cells become JSON numbers, booleans and null. Values with leading zeros, such as 007, stay strings so IDs are not damaged.
My file uses semicolons. Will it work?
Yes, choose the semicolon delimiter. Many European spreadsheets export with semicolons because the comma is their decimal separator.
What is "Neutralise formulas"?
A spreadsheet runs any cell that starts with =, +, - or @ as a formula, so untrusted data in a CSV can exfiltrate data or run commands when opened in Excel (CSV injection). With this on, such text cells get a leading single quote. Plain numbers such as -5 are left alone. Turn it off if you need the exact text.
What JSON can be converted to CSV?
An array of flat objects. Keys from every object are merged into columns, and nested objects or arrays are written as JSON text in the cell.