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Input (CSV)
Output (JSON)
How to use: Choose a conversion mode and enter data on the left to see the result on the right in real time. CSV → JSON handles double-quoted fields, escaping (""), and line breaks inside fields. For JSON → CSV, enter an array of objects (e.g. [{"name":"Tanaka","age":30}]).
📖 If you just want to format or validate JSON, the JSON Formatter / Validator is handy. We also offer free learning posters that illustrate how data and the web work.

Frequently Asked Questions (FAQ)

What is CSV?

CSV (Comma-Separated Values) is a text format that represents tabular data with fields separated by a delimiter such as a comma. Each line corresponds to one record, and it is widely used for exchanging data with Excel, spreadsheets, and various databases. When a value contains a comma, a line break, or a double quote, the whole field is wrapped in double quotes and inner double quotes are escaped by doubling them.

What is a header row?

A header row is the first line of a CSV that lists the name of each column. When "Use first row as header" is enabled, CSV-to-JSON conversion outputs an array of objects keyed by the header names. When it is disabled, it outputs an array of arrays, treating each row as a plain array. For JSON-to-CSV conversion, the object keys become the header row.

Is my input data sent to a server?

No. Conversion between CSV and JSON happens entirely in JavaScript inside your browser. The data you enter is never sent to or stored on a server, so you can safely convert data that contains confidential information.

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