About two weeks ago I built a small text-comparison tool as a simple front-end project. Recently I ran into another annoyance: converting CSV/Excel/JSON with tools that upload files to servers, feel slow, or impose limits. Since I prefer privacy-first tools, I built this one as well.

100% local: All parsing and conversion run in Web Workers. No uploads.

Format support: CSV ↔ Excel (.xlsx), JSON, SQL, XML, Markdown.

Smart column restoration: Fixes copied tables that collapse into a single column (enable under “More Options”).

No size limits: Only limited by your RAM.

My goal is to grow this into a small, one-stop CSV/format toolbox. It just launched, so there may be rough edges — feedback is welcome.

Tech

Next.js, Tailwind, SheetJS, Web Workers, i18next.

Looking for feedback

Try it with your odd CSVs: unusual delimiters, quoted newlines, mixed encodings, huge files, broken pasted tables. Also curious whether the column-restoration feature feels intuitive.

Thanks for checking it out!