Question 1

When was the CSV format first used in computing?

Accepted Answer

CSV (Comma-Separated Values) has been used since at least 1972 on IBM Fortran compilers, over a decade before personal computers became common. Despite its age and ubiquity, CSV was not formally standardized until RFC 4180 was published in 2005. The format's simplicity — plain text with a delimiter — is exactly why it has outlasted more complex data interchange formats in many workflows.

Question 2

How does dot-notation flattening work for nested JSON?

Accepted Answer

When "Flatten nested" is enabled, nested objects are collapsed into a single level using dot-separated keys. For example, {"user":{"address":{"city":"Paris"}}} becomes a column named "user.address.city" with the value "Paris". Arrays are serialized as JSON strings rather than flattened, because arrays don't map cleanly to a single CSV column. This approach preserves all data while keeping the CSV readable in spreadsheet software.

Question 3

How are commas and newlines inside values handled in the CSV output?

Accepted Answer

The converter follows RFC 4180 quoting rules: any field containing the delimiter character, double quotes, or line breaks is wrapped in double quotes. Double quotes inside a field are escaped by doubling them (""). This means a JSON value like "hello, world" becomes the CSV field "hello, world" (wrapped in quotes), which Excel, Google Sheets, and other tools parse correctly without splitting the field.

JSON ↔ CSV Converter

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