No upload · No size limit · No watermark · No signup
Convert CSV, JSON and Excel files
Turn CSV into JSON, JSON into Excel, Excel into CSV — any direction. Your file is parsed and converted locally in your browser, so the data never leaves your device.
How it works
- Drop a .csv, .json or .xlsx file. It stays on your device.
- Check the preview and pick the output format.
- Download the converted file — rows and columns intact.
Frequently asked questions
Is my file uploaded to a server?
No. The file is parsed and converted entirely in your browser using JavaScript — it never leaves your device, so it works even offline once the page has loaded.
Does it handle commas, quotes and line breaks inside CSV cells?
Yes. Parsing and writing use SheetJS, a battle-tested spreadsheet engine, so quoted cells containing commas, double quotes and line breaks follow standard CSV quoting rules in both directions.
What JSON shape does the converter expect and produce?
An array of objects, where each object is one row and its keys become the columns — the shape most APIs and libraries use. Converting to JSON produces the same shape. Nested objects are kept as JSON text inside the cell.
Is there a file size limit?
Files up to about 50 MB convert comfortably — beyond that, in-memory spreadsheet parsing can make a browser tab sluggish, so the tool asks for a smaller file instead of freezing.
Why do some cells in my CSV download start with an apostrophe?
Text cells that begin with =, +, - or @ can be executed as formulas when a CSV file is opened in Excel or Google Sheets — an attack known as CSV injection. To keep downloads safe to open, the converter prefixes those text cells with a single apostrophe, which spreadsheet apps treat as literal text. Numeric cells, including negative numbers, are never changed.