Most "free CSV converters" ask you to upload a file. That file is often a payroll export, a customer list, or a client's data. The moment it leaves your machine, you became a data exporter.

A privacy policy does not undo that.

There's a simpler test: open DevTools → Network, drop the file, and watch. If any request fires, the file left your device.

NoCloudCSV is built so that request cannot happen. Every tool page ships connect-src 'none' — the browser blocks outbound connections, including from injected scripts. Load it once, switch to airplane mode, keep working.

Live now (free, no signup): remove duplicate rows, split CSV, CSV → JSON, JSON → CSV.

Shipping next, still fully local: join/merge, Excel ↔ CSV, anonymize columns.

If you handle other people's data, stop trusting upload forms. Verify the Network tab instead.