An account is optional, and every exercise works without one. Signed out, Solfege does not know who you are and nothing about how you practise leaves your browser unless you accept Google Analytics. It never records you. There is no advertising and no cross-site tracking, and the microphone is never accessed.
Visits are counted with Cloudflare Web Analytics, which is cookieless and sets no cookie. Per page view it records the page address, the referring page, your browser and operating system, the country derived from your IP address, and how long the page took to load. Cloudflare states it does not store the IP address itself. The lawful basis is legitimate interest under GDPR Art. 6(1)(f).
With your consent, the site also uses Google Analytics 4, which sets a _ga cookie. It then also records pressing play, new exercises, whether an answer was right, wrong or revealed, lesson picks, level unlocks, opening settings and audio failures, plus a short summary when you leave or switch away from a page: the last action and how long ago it was, counts of plays, exercises and answers, the run of wrong answers, whether something was playing or audio had failed, and how many times you switched away. It never sends the notes or anything you entered (a share link's melody is removed from the page address first), and the microphone is not used. Google Analytics is off by default. You can grant or revoke consent on this page when JavaScript is enabled. Advertising signals are denied unconditionally.
If you sign in, with Google or with a one-time link sent to your email address (no password), the account runs on Google Firebase (Authentication and Cloud Firestore, settings and tally stored in the EU region eur3), a processor. It holds your name and profile-picture address if you used Google, your email address, an account id, a copy of your settings, and a tally recorded only while you are signed in: time and exercises per solfège lesson, interval and chord questions asked and answered right first time, and time on sight-singing. Signed in, and on the account page, the browser talks to identitytoolkit.googleapis.com, securetoken.googleapis.com, firestore.googleapis.com and, during sign-in, accounts.google.com, apis.google.com and the site's own sign-in address (relayed to Firebase's firebaseapp.com), which an emailed sign-in link also passes through. The browser keeps your account id and one letter for the account icon (solfege.account.v1), and the address a link was requested for until you open it (solfege.account.email.v1). A visitor who is not signed in contacts none of them. The lawful basis is contract (GDPR Art. 6(1)(b)). Deleting the account on the account page erases all of it.
Your theme preference, each exercise's settings and a running total of time on the site are kept in your browser's local storage. They are never transmitted unless you sign in, and clearing your browser data removes them. Signed in, the browser also keeps the Firebase session and Firebase's record of the days its code ran in IndexedDB (firebaseLocalStorageDb, firebase-heartbeat-database; both are created on the account page even before signing in) and three localStorage keys: solfege.account.v1, solfege.progress.pending.v1 and solfege.settings.pending.v1.
The feedback form on the home page is the only place the site sends anything you have typed; it is delivered by Web3Forms. Last updated 9 October 2026.