The short answer
Nothing Roosta needs to wake you touches the network. Alarms are scheduled locally, all 21 sounds ship inside the app, and camera missions run their recognition on the device. Roosta works in airplane mode, with no SIM, and with no Wi-Fi.
The rule
No cloud inference, no remote configuration fetch, no authentication refresh anywhere on the path between an alarm firing and you dismissing it. A user with no signal must still wake up. That constraint is what shapes several other decisions in the app.
- All 21 alarm sounds are bundled with the app rather than streamed.
- Camera missions run recognition on-device, which is also why frames never leave your phone.
- Mission content — problems, phrases, sequences — is generated locally.
- There is no advertising, so nothing has to load before you can silence the alarm.
Why other alarm apps break offline
Three patterns are common in this category, and each turns a lost connection into a failure at the worst possible moment.
- An advert on the ring or dismiss screen. If the ad must load first, no network means a stuck screen while the alarm keeps sounding.
- Cloud-based verification — a photo uploaded for matching, or a puzzle fetched from a server.
- Music-service integration used as the alarm sound, which needs a connection to play.