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Bulk CSV/Excel to JSON

Turn messy client CSV and Excel sheets into clean JSON arrays or keyed objects with column mapping. Developers convert 50 exports without hand-editing — local SheetJS work, 2 free batches a day.

Runs on SheetJS

100% Local Browser Native

How to Use the Bulk CSV/Excel to JSON

1. Upload CSV or Excel

Client exports and multi-sheet workbooks. Standardize headers (date, vendor, amount) before upload.

2. Map and shape output

Review column mapping; choose merged single JSON or separate files, array-of-objects or keyed-by-ID.

3. Download JSON

Formatted output ready for APIs or configs. The save counts as one Pro download.

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Frequently Asked Questions

Array or keyed-object JSON — which output?

Array-of-objects for APIs and databases; keyed-by-ID objects for lookups and configs. Convert once per shape: a 50-file client dump becomes one merged array or 50 keyed files, your choice per batch.

What if columns differ across files?

The tool unions all headers; missing cells become null. Standardize supplier exports first — renaming Date, Vender, AMT to date, vendor, amount before upload saves an hour of post-cleanup.

How large a spreadsheet converts reliably?

Tens of thousands of rows per file convert in seconds locally. Past ~100k rows, split by month or region — browsers slow on giant single sheets, and smaller files validate faster.

Are my spreadsheets uploaded anywhere?

No — parsing runs locally in your browser with SheetJS; client data never leaves your device. Only the final JSON save counts as one Pro download.

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Last updated October 2026