How are nested objects flattened?

Nested objects become dot-path columns (address.city). Lists of plain values are joined with '; ' in one cell; lists containing objects stay as compact JSON text in one cell so one record stays one row. The rule is printed on the page.

Why does Safe export add an apostrophe?

A cell beginning with =, +, - or @ can be treated as a formula by Excel or Google Sheets. Safe export prefixes such fields with an apostrophe so they open as plain text instead of running as formulas.

Is anything uploaded?

No. JSON is parsed and converted in your browser tab. Nothing is uploaded, stored or shared.

JSON в CSV — конвертер онлайн