Drag, Drop, JSON
Your project manager keeps the feature roadmap in a spreadsheet. Your React dashboard needs that data as JSON. You could write a script, but then you’d have to explain to your PM how to run it next time the spreadsheet changes.
Instead: drop the .xlsx straight in, or upload a CSV/TSV export. The tool reads the file in your browser — nothing gets uploaded to any server. Native Excel workbooks are parsed with the xlsx library (it pulls the first sheet); CSV and TSV files are parsed directly, with delimiter auto-detection (commas, tabs, or semicolons). Either way it infers data types (numbers stay as numbers, booleans become true/false) and spits out a properly formatted JSON array.
Working With It
Upload an .xlsx, .xls, .csv, or .tsv file (or drag and drop it). For text files, if auto-detection guesses the wrong delimiter, override it manually. The JSON appears with proper indentation.
A CSV with columns “name, email, department” and 50 rows produces a JSON array of 50 objects. Numbers convert to JSON numbers, true/false values become booleans, and empty cells become null.
Where This Fits In
Legacy system exports. That old inventory system exports TSV files. Your new app speaks JSON. Upload the TSV, copy the output, and feed it into your MongoDB import script.
Config management. Some teams manage feature flags or configuration in spreadsheets because non-technical stakeholders can edit them. Export as CSV, convert here, and your app reads it as JSON.
Test fixtures. QA maintains test scenarios in a spreadsheet. Convert the whole thing to JSON and import it as test data in your automated tests.
Frontend prototyping. Need 50 rows of data for your React table component? If the data exists in a spreadsheet, it’s faster to convert than to type JSON by hand.
Native .xlsx, Handled
You don’t have to convert anything first. Drop a real .xlsx (or older .xls) and the tool reads the binary workbook directly in the browser, pulling rows from the first sheet. Multi-sheet workbook? Only the first sheet is converted, so split sheets into separate files if you need each one. Empty cells come through as null.
If you’d rather paste CSV data directly instead of uploading a file, the CSV to JSON tool does that. For the reverse operation (JSON to a spreadsheet-friendly format), the JSON to Excel converter produces BOM-encoded CSV files that open correctly in Excel.
The file never leaves your device. It’s read locally, and all conversion happens in your browser.