Step 1 / source
Choose the source
Drop one file here
Choose a JSON export whose top-level array contains records made from strings, numbers, booleans, or null values.
Checking publication status...LOCAL DATA CONVERTER / JSON TO XLSX
JSON to Excel
Turn a flat JSON record array into a genuine XLSX worksheet with typed scalar cells, a frozen header row, filters, and readable widths.
Processed in this browserOne UTF-8 .json file up to 5 MB. The top level must be a non-empty array of flat objects, limited to 50,000 records, 200 columns, 1,000,000 cells, and 20 MB output.
JSON - 50,000 records
No file upload
This operation runs with browser APIs. Nirmion receives catalogue requests, not the selected source bytes.
Original stays unchanged
The converter creates a separately named output. It never writes back into the source file.
Bounded work
One UTF-8 .json file up to 5 MB. The top level must be a non-empty array of flat objects, limited to 50,000 records, 200 columns, 1,000,000 cells, and 20 MB output.
Plain-language method
How JSON properties become worksheet columns
Nirmion validates every array item as a flat object, builds columns in first-seen property order, places missing properties in empty cells, and writes scalar values to a newly generated XLSX worksheet. Nested objects and arrays are rejected rather than hidden as ambiguous text.
- 01Choose a valid source
Use a top-level JSON array such as [{"id":1,"name":"Ada"}]. Flatten nested addresses, line items, or child arrays before selecting the file.
- 02Review the conversion choices
Preserve types keeps numbers and booleans as worksheet values. Text mode converts non-null values to text when identifiers or display consistency matter more than typing.
- 03Inspect the separate result
The download ends in _nirmion_tools_records.xlsx with a styled first row, filter controls, frozen headers, and no macros or external links.
Useful when
Practical jobs this tool handles
- Open an API record export in a spreadsheet.
- Give non-technical reviewers a filterable JSON table.
- Preserve numeric and boolean values in a portable workbook.
Before converting
Prepare a rectangular record set
- Confirm the top level is an array, not one object.
- Flatten nested objects and arrays into scalar properties.
- Review identifier columns before choosing typed or text mode.
Know the boundary
Flat records only
A worksheet cell cannot preserve arbitrary nested JSON structure. Nested objects and arrays stop the conversion so no hierarchy is silently stringified or lost.
Quick answers
Questions before you convert
The contract favours predictable tables over guessed flattening.
Are JSON numbers kept as numbers?
Yes in Preserve types mode; Text mode deliberately writes their visible values as text.
What happens when records have different properties?
The union of property names becomes the header, and missing properties produce empty cells.
Can it convert one JSON object?
No. Wrap record objects in an array so the worksheet row contract is explicit.