BackToPhone does not send browsing data off your computer. The free features stay on your device.

It stores, in your browser profile:

• whether the extension is on
• your per-website choices (stop hidden sound, silence site, watch only, leave alone)
• extra websites you turned on with Use it on this website
• whether Use on every website is on
• a short list of times it stopped or noticed a hidden sound (time, website, what it did)

It also keeps a short-lived count on the toolbar icon for the current tab. That count goes away when the tab closes or the browser session ends.

Pay (optional). If you buy Silence site + every website ($4.99 once), the extension talks to ExtensionPay (https://extensionpay.com) and Stripe so they can take payment and remember that you paid. That is the only network call. You choose it by clicking Unlock. Free Stop hidden sound never needs that.

It does not include analytics. Uninstalling the extension removes local storage. Paid status is held by ExtensionPay; use Already paid? to restore it on another browser.

It starts with shopping sites (AliExpress regional sites and Temu). Extra sites are added only when you click Use it on this website (one site) or Use on every website. You can turn either off from the popup or from the browser's extension settings.

To be able to ask at all, the extension declares optional access to every website, so your browser's extension listing will mention broad site access. Optional means it is never granted up front: nothing is added until you click those buttons, and you can see exactly which sites are granted in your browser's extension settings at any time.