XLSX to JSON Converter

Convert spreadsheet rows into JSON objects

Developers, analysts and operations teams often receive structured data as an Excel workbook even when the next step needs JSON. This XLSX to JSON converter turns a worksheet into an array of objects that can be used in scripts, prototypes, static sites, imports and API tests. Upload a workbook, select the relevant sheet and the first row becomes the object keys for every following row.

The file is handled entirely inside your browser with SheetJS. The workbook is read from the local file object, transformed in memory and previewed as formatted JSON. No spreadsheet data is uploaded, logged or stored elsewhere. That private workflow is useful for sample exports, migration planning, catalog data, internal reports and any workbook that should not be pasted into a server-based converter.

Preparing a sheet for clean JSON

A simple rectangular table converts best. Put field names in the first row and avoid duplicate column labels, because each label becomes a JSON property. Keep notes, totals and merged title blocks outside the selected sheet or remove them before conversion. Blank cells are preserved as empty values so rows keep a consistent shape, which is helpful when the JSON will be inspected by another script or imported into a database.

How to use the result

The downloaded file is a standard UTF-8 JSON document. You can commit it into a static project, load it in Node.js, feed it into a data import process or open it in an editor for quick review. For very large sheets, preview only the beginning on the page and rely on the downloaded file for the full content. If the data needs to return to spreadsheet format later, keep the original workbook as the authoritative source.

Output details to know

The output is a JSON array with one object per data row, pretty-printed with two-space indentation. A sheet whose first row contains the headers name, qty and price becomes a list of objects that each have those three properties. Numeric cells stay numbers, text cells stay strings and empty cells become empty strings. If two columns share a header, the converter makes the keys unique by appending a suffix such as _1.

Date cells may appear as numeric serial values rather than formatted text, so check them in the preview and convert them in your own code if needed. The status line reports how many rows were converted. The preview is limited to the first 25,000 characters, but the downloaded file contains everything. Only the selected worksheet is converted, so export each sheet you need separately.