Last updated: October 2026
You can use Psst without an account. Until you sign in, we create an anonymous guest account that holds no name, email or Google ID. It is identified only by a random key stored in your browser (we keep a one-way hash of it). If you uninstall the extension or clear its data, that key is gone and the guest account can't be reached any more.
If you sign in with Google, we receive and store:
As you use the extension, we store your vocabulary progress, quiz history, and settings (chosen language, daily goal, notification preference).
Your data is used solely to provide the Psst service — syncing your learning progress across sessions and personalising your quiz experience. We do not sell, share, or use your data for advertising.
The extension stores your session token and cached user info in chrome.storage.local on your device. This data never leaves your browser except to communicate with the Psst API at lingopop.istos.dev.
Premium purchases are processed by Lemon Squeezy, our Merchant of Record. Lemon Squeezy handles checkout and billing and receives the details you enter at checkout (such as your email and payment information). We never receive or store your card details.
Sign-in is handled by Google OAuth, and payments by Lemon Squeezy (above). No other third-party services receive your personal data.
This website (psst.istos.dev) uses Umami, a privacy-friendly analytics tool that we host ourselves, to count page visits and clicks on buttons such as "Add to Chrome". It uses no cookies, does not store IP addresses, and the data never leaves our own server. The Psst extension itself contains no analytics.
Your account and progress data are retained as long as you have an account. You can delete it at any time from Settings ("Delete account", or "Delete my data" for a guest), or by contacting us. When a guest signs in with Google, the guest's progress moves to that Google account.
Questions or deletion requests: [email protected]