How to Convert JSON to CSV or Excel Safely

Converting JSON to a spreadsheet format is a common task for developers, analysts, and anyone working with API data. Filelume lets you convert JSON to CSV and XLSX entirely in your browser, without uploading your data to any server.

Why convert JSON to a spreadsheet?

JSON is excellent for data exchange but awkward for analysis. Spreadsheet applications like Excel, Google Sheets, and LibreOffice Calc expect tabular data. Converting JSON to CSV or XLSX lets you:

Sort and filter data using familiar spreadsheet tools
Create charts and pivot tables
Share data with colleagues who do not work with JSON
Import data into databases and other systems

How to convert JSON with Filelume

Open the JSON Viewer.
Load your JSON file.
Switch to Table view to confirm the data is detected as tabular.
Click Export CSV or Export XLSX.

The export uses the currently detected dataset. If your JSON contains multiple record arrays, you can choose which one to export.

CSV export details

Filelume's CSV export produces standards-compliant files:

UTF-8 encoding with optional BOM
Proper quoting of fields containing commas, quotes, or newlines
CRLF line endings for maximum compatibility
Formula-injection protection to prevent spreadsheet attacks
Configurable delimiter

XLSX export details

The XLSX export produces a genuine Excel workbook:

Proper .xlsx format (not renamed HTML or CSV)
Safe sheet names with length limits
Multi-sheet support for files with multiple datasets
Header row frozen for easy scrolling
Bounded column widths for readability
Formula-like strings preserved as plain text

When is a JSON file tabular?

Filelume enables CSV and XLSX exports only when a valid record structure is detected. This prevents misleading conversions. Valid structures include:

Root arrays of objects with consistent keys
API envelopes containing data arrays
Objects where values are similarly shaped records
Arrays of primitives (exported as a single-column table)

If your JSON is deeply nested without a clear record structure, the Tree and Formatted views remain available for inspection.

Security considerations

When converting data for spreadsheets, formula injection is a real concern. Malicious strings like =CMD() in a CSV field could execute formulas when opened in Excel. Filelume neutralizes this risk by prefixing formula-like strings with a single quote, keeping them as plain text.

No upload, no account

The entire conversion happens in your browser. Your JSON data never leaves your device. Open the JSON Viewer, load your file, and export — all within seconds.