Private by construction
porto.tools is private because of how it is built, not because of a promise. Every conversion runs inside your browser using WebAssembly. Your files are never sent to a server, because there is no server in the path.
Your files never leave your device
When you drop a file, it is read and processed locally and the result is handed back to you for download. The file contents are never uploaded, streamed, or copied off your machine. You can confirm this: turn off your network after the page loads, and the tools still work.
No account, no file history
There is no sign-up and no login. We do not store your files, keep a history of what you converted, or attach any of it to an identity. Files live only in your tab's memory and are gone when you close it.
What the site itself collects
The website may use privacy-respecting analytics to count page visits, and may show ads on some pages to keep the tools free. These never receive your file contents, only ordinary page-level information, and any cookies are gated behind your consent. The conversion engine and the on-device guarantee are unaffected by either.
Open source
The conversion engine source is on GitHub under the GNU AGPL-3.0 (dual-licensed AGPL-3.0 or commercial) — the on-device claim is auditable, not just asserted. If you want to verify how a tool handles your file, you can read the code.