Free JSON ↔ CSV Converter

One level of nesting is flattened into dot-notation columns: {"user": {"name": "Ana"}} becomes a column called user.name. Deeper structures and arrays inside objects are serialized as JSON strings in their cell so no data is lost. CSV is a flat format, so deeply nested JSON always involves a flattening decision — dot keys are the convention most tools round-trip cleanly.

No hard limit — the constraint is your browser's memory, since everything runs locally. Files up to a few megabytes (tens of thousands of rows) convert effectively instantly. Very large files may make the tab work for a moment; for multi-hundred-megabyte datasets, a command-line tool or database import is the better instrument.

Excel assumes a legacy encoding unless the file starts with a UTF-8 byte-order mark (BOM), so accented characters and symbols get mangled on open. The fix on Excel's side: use Data → From Text/CSV and choose UTF-8 as the file origin, which imports the same file correctly. Google Sheets and most other tools detect UTF-8 automatically.

No. The conversion runs entirely in your browser using JavaScript on this page — no request carries your data to any server, ours included. You can verify this with your browser's network inspector: pasting and converting triggers zero network activity. Closing the tab removes everything.

An array of objects — [{"a": 1}, {"a": 2}] — which is what APIs and exports almost always produce. A single object is treated as a one-row array. The header row is the union of every key across all objects, so rows with missing keys simply get empty cells rather than misaligned columns.

Per the CSV standard (RFC 4180): any field containing a comma, double quote, or line break is wrapped in double quotes, and quotes inside it are doubled (" becomes ""). Going the other way, the CSV parser understands the same rules, so values with embedded commas and multi-line cells survive a round trip intact.