Sona for Android
The Android app is live on Google Play — the same account, your decks downloaded for offline study, and answers that sync when you're back.
Sona is on Google Play now. Sign in with the account you already have — there's nothing to import and nothing separate to set up.
The same account, not a companion app
Open the app and your decks are already there. A study session you start on your phone picks up on web exactly where you left it, and the other way around, because it's the same session underneath, not a copy synced after the fact. Study, Browse, and every Quiz format work the way they already do on web; what actually separates the three hasn't changed by moving to a phone.
Download a deck before you need it
Each deck has a download toggle. Turn it on and the deck comes down to the device — cards, and anything embedded on them, images and audio included. A downloaded deck works with no connection at all: Study, Browse, and Quiz, including starting a brand-new session, not just resuming one you'd already begun online. A deck you haven't downloaded still needs a connection to open, the same as an undownloaded deck on the web app.
If your queue tends to pile up on a commute or a trip, download the decks you review most before you actually need them, not after.
What syncs, and when
Answers you give offline are queued on the device and pushed the moment you're back online — on opening the app, on reconnecting, and right after each answer while you're already connected. The server is still the one place scheduling is decided; a downloaded deck's own FSRS math runs locally just so a review doesn't have to wait on a connection, and it's reconciled against the server the next time it syncs. None of this sits behind a paywall — sync, offline access, and everything Study, Browse, and Quiz do are unlimited on the Free plan, on both platforms.
If you've been away for a while and the queue looks bigger than you remember, that number means less than it looks — the same is true whether it built up on your phone or your laptop.
iOS is next
An iOS build already exists and is in TestFlight, but the App Store listing itself isn't submitted yet. When that changes, it'll be here first.
For now: if you're on Android, get the app and sign in. Your decks are waiting either way.