JSON to CSV & Excel Converter — Nested Objects, Any File Size
Paste or drop your JSON — nested objects flatten automatically into clean columns. Live table preview, custom delimiters, zero uploads. Works for files of any size without freezing.
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Frequently Asked Questions
Nested objects and arrays are recursively flattened into dot-notation column headers — e.g., user.address.city becomes a single CSV column. Arrays of primitives are joined with commas.
Yes. Conversion runs in a dedicated Web Worker thread with a progress bar. Even JSON arrays with hundreds of thousands of rows convert smoothly with no UI freeze.
No. There is no artificial cap — your system's available RAM is the only constraint. This tool handles what server-based converters reject, without uploading anything.
Yes. Both formats are generated simultaneously. Excel (.xlsx) works for up to 100k rows; larger datasets generate a streaming CSV download instead.
Comma, Tab, Semicolon, and Pipe. Switch delimiters from the toolbar — the CSV output previews the change instantly without re-running conversion.
No. All conversion runs entirely in your browser. Your JSON — including any sensitive fields — never leaves your device.