Convert JSON to XLSX Online Free — No Upload, Formatting Kept
Turn JSON arrays and objects into real Excel .xlsx workbooks right in your browser — column order and types stay intact. No upload, no signup, no limits.
Drop .json files here, or click to browse
Supports .json · processed locally · never uploaded
How to Convert JSON to Excel Online
- Drop one or more .json files — everything is processed locally and never uploaded.
- Click Convert to XLSX — arrays of objects are mapped to sheets, one column per field.
- Check the report — each result lists the sheets that were written.
- Download the result — a single workbook downloads directly; multiple files come back as a ZIP.
How the Conversion Works
Every row object contributes its keys: the header row is the union of all keys in first-appearance order, so a field that only appears in row ten still gets its column. Missing keys and null values become empty cells, numbers and booleans keep their types, and date strings are written as plain text exactly as they appear in your JSON.
Nested objects and arrays cannot live in a single cell, so they are serialized as JSON strings — round-trip them through our XLSX to JSON converter to get the original structure back. An empty array still produces a (blank) sheet, and sheet names are cleaned to what Excel allows: at most 31 characters, without \ / ? * [ ] or :.
The output is a genuine .xlsx file — open it in Excel, LibreOffice or Google Sheets with formatting, filtering and formulas intact for further editing.
Supported JSON Shapes
| JSON input | Resulting workbook | Notes |
|---|---|---|
| [ {...}, {...} ] | One sheet named “Sheet1” | The most common API/export shape |
| { "Users": [...], "Orders": [...] } | One sheet per key, in key order | Sheet names come from the keys |
| { "Empty": [] } | A blank sheet named “Empty” | Empty arrays are not skipped |
| 42, "text", null | Rejected | Top level must be an array or an object |
| [ [1,2], [3,4] ] | Rejected | Rows must be objects, not arrays |
Why a Real Workbook Instead of CSV
| XLSX (this tool) | CSV | |
|---|---|---|
| Sheets | Many sheets in one file | One table per file |
| Types | Numbers and booleans stored natively | Everything is text, re-guessed on import |
| Quoting pitfalls | None — values live in XML cells | Commas, quotes and newlines need escaping |
| Excel compatibility | Native format, opens instantly | Encoding and delimiter surprises |
Privacy and Limitations
- Files never leave your device — parsing and workbook generation happen in your browser.
- One header row per sheet is generated from your keys; styling, formulas and charts are not part of the conversion.
- Sheet names longer than 31 characters are truncated; duplicates get a numeric suffix.
- Very large arrays are limited by the memory of one browser tab.
Frequently Asked Questions
Is this JSON to Excel converter free?
Yes — 100% free with no sign-up, no watermark and no file limit. All conversion happens locally in your browser.
How are the columns ordered?
Columns follow the first appearance of each key across all rows — not just the keys of the first row. A field that shows up later still gets its own column in discovery order.
How do multiple sheets work?
Give an object whose values are arrays: every key becomes one sheet, in key order, with the key as the sheet name. A top-level array becomes a single sheet named Sheet1.
What happens to null and missing fields?
They become empty cells. Every column still exists in the header row, so the table stays rectangular and easy to filter.
What about nested objects or arrays?
A spreadsheet cell cannot hold a structure, so nested values are serialized as JSON text. Convert the workbook back with our XLSX to JSON tool to restore the original structure.
Will my file be uploaded to a server?
No. The JSON is parsed and the workbook is built by JavaScript in your browser; your file never leaves your device.
Why is a sheet name shorter than in my JSON?
Excel limits sheet names to 31 characters and forbids \ / ? * [ ] :. Longer or invalid names are cleaned automatically — duplicates receive a numeric suffix.
Related Tools
Need to view or edit the generated workbook?
Open the free online Excel editor