Privacy

Your files are processed in your browser and are never uploaded.

What stays on your device

• The template and spreadsheet you drop in, everything typed into the form, and the files the tool makes. They are read and written by this page on your computer and are not sent to any server.
• The page is served with a content security policy that only lets it talk to its own address.

What the site records

• Anonymous events: a page visit, that the tool was used, that a download happened, that the paid button was pressed. Each event stores the event name, the page path, the time and a short note made of counts (for example "rows=247;ready=244").
• If you send a note in the feedback box, its text (up to 500 characters). Please do not put names or TINs in it.
• No IP address, no browser details, no cookies, no account. Events are deleted after 120 days.

Browser storage

The site sets no cookies. If you buy a season pass, a marker is saved in this browser's local storage so the tool stays unlocked.

Payments

The tool is free during launch and takes no payment details.

Perfrow is an information tool, not tax, legal or professional advice. Last updated 2026-11-10.