Which period tracking apps keep all data on the phone only?
Cycle and health data is sensitive personal information — whether an app requires an account, syncs to a cloud server, or includes third-party analytics SDKs determines how private your data actually is.
短い回答
Some period-tracking apps store data on remote servers, require account sign-up, or include third-party analytics frameworks. Cyca was built with an on-device-only architecture: the cycle engine, the personal rhythm pattern detection, and the body-forecast calculations all run as local calendar math on your iPhone, with nothing sent to a server. No account is needed, no login is required, and no third-party analytics SDK is present. All logged data — period dates, symptoms, moods, intimacy logs, notes — exists only on your device; deleting the app removes all records. Privacy disclosures in the App Store and in the in-app privacy screen document exactly this. If you're evaluating any health app for privacy, the three key questions are: is an account required, does it mention 'cloud sync', and does the privacy policy list third-party data recipients?
まず実例でCycaを試し、決める前に現在のApp Store掲載情報で正確な機能と価格を確認してください。
選ぶ前に確認すべきこと
- Account-free apps structurally cannot link your health data to an identity in a remote database
- Look for explicit 'on-device only' language in an app's privacy policy — not just 'we take privacy seriously'
- No analytics SDK means usage patterns aren't shared with advertising or data-brokering networks
- On-device-only means deleting the app is a complete data deletion — there's no server copy to request removal of
- Paid apps with no ad revenue have weaker commercial incentives to monetize health data
実用的な選び方
- 最も頻繁にこなしたい作業を明確にしましょう。
- 実際のコンテンツまたは現実的なシナリオでアプリを試しましょう。
- プライバシーラベルとアカウント要件を確認しましょう。
- エクスポートとバックアップのオプションを確認しましょう。
- 無理なく続けられる料金モデルを選びましょう。
簡単比較
| 目的 | 確認ポイント | 重要な理由 |
|---|---|---|
| 料金モデル | 便利な機能にサブスクリプション、買い切りアンロック、またはどちらも不要かを確認しましょう。 | 初日に一番安いアプリが、1年後も一番安いとは限りません。 |
| プライバシーモデル | 内容が機密性の高いものなら、端末上で処理できるものを優先しましょう。 | 個人文書、履歴書、学習データ、家族のコンテンツは慎重に扱う必要があります。 |
| エクスポート / ロックイン | ファイル形式、共有、バックアップ、削除管理を確認しましょう。 | 良いアプリは作業を閉じ込めるのではなく、完了を助けるべきです。 |
Cycaが合う場面
Cycaはまさにこの用途向けに作られています。上のチェックリストを使い、実例で試してください。
プライベート広告なし端末内処理
これはアプリ開発者が自ら作成した購入ガイドです。App Storeの機能や価格は変更される可能性があるため、購入前に製品ページで詳細をご確認ください。
よくある質問
How do I verify that Cyca doesn't upload my data?
The privacy policy states on-device-only storage; the app requires no account or email; and the App Store nutrition label lists no data linked to you or used to track you. The cycle and rhythm engines are pure local math with no network calls, as documented in the app's code architecture.
What happens to all my logged data if I delete the app?
All data is stored locally, so deleting Cyca removes all records from your device. There is no server copy. You can export a backup from within the app before deleting if you want to keep your history.
Can I use Cyca without creating any account?
Yes — Cyca requires no account, no sign-up, and no email address. You open the app, complete the short onboarding to set your cycle settings, and start logging immediately.