What spreadsheet formats does this support?

It writes .xlsx files when you click download, and reads both .xlsx and .xls files back into JSON when you use Open spreadsheet; older formats like .ods aren't supported.

How are the spreadsheet's column types decided?

Each column is scanned across every row: if every value is a number it becomes a numeric column, if every value is a boolean it becomes a boolean column, and anything mixed defaults to plain text.

Does the file get uploaded anywhere to convert it?

No. Both generating the .xlsx file and reading an uploaded spreadsheet happen in your browser; the file never leaves your device, which matters for spreadsheets containing real business data.

What happens to null or missing fields in a row?

A missing or null field is written as an empty cell in the spreadsheet, and reading a blank cell back produces null in the resulting JSON object for that key.

JSON ↔ Excel

Turn a JSON array of objects into an Excel (.xlsx) file, or read a spreadsheet back to JSON, locally.

Local, Runs entirely in your browser, your data never leaves your device.

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Turn JSON records into a downloadable spreadsheet

This tool builds a real .xlsx workbook from a JSON array of objects, and reads an existing spreadsheet back into JSON. It's aimed at handing structured data to someone who works in Excel, or pulling rows out of a spreadsheet someone sent you without opening Excel yourself. The file is generated and parsed entirely in your browser, so a spreadsheet full of customer records or pricing data never touches a server.

How to use the JSON ↔ Excel

Paste a JSON array of objects into the editor, or load the example data.
Set a file name, then click Download .xlsx to generate the spreadsheet.
Click Open spreadsheet… to import an existing .xlsx or .xls file instead.
Check the row count shown above the editor to confirm every record loaded.

Column types are inferred per field: a column where every value is a number is written as numeric, an all-boolean column as boolean, and anything mixed or textual falls back to text. Nested objects and arrays inside a row are converted to a JSON string rather than split into extra columns.

Frequently asked questions

What spreadsheet formats does this support?: It writes .xlsx files when you click download, and reads both .xlsx and .xls files back into JSON when you use Open spreadsheet; older formats like .ods aren't supported.
How are the spreadsheet's column types decided?: Each column is scanned across every row: if every value is a number it becomes a numeric column, if every value is a boolean it becomes a boolean column, and anything mixed defaults to plain text.
Does the file get uploaded anywhere to convert it?: No. Both generating the .xlsx file and reading an uploaded spreadsheet happen in your browser; the file never leaves your device, which matters for spreadsheets containing real business data.
What happens to null or missing fields in a row?: A missing or null field is written as an empty cell in the spreadsheet, and reading a blank cell back produces null in the resulting JSON object for that key.