Privacy

Updated October 24, 2026. CoHours is run by its solo developer. Questions: hello@cohours.com.

What is stored

No account or sign-in is required. A random browser ID in local storage connects this browser to its records. A browser ID is not a verified person: different browsers may belong to the same person.

Cloudflare stores the browser ID, study sessions and minutes, materials and goals you enter, reservations, room presence, invitations, Circle membership and messages, safety reports, and optional notification subscriptions. Basic usage events include visits, starts, completions and invitation actions, with the referral code from the link. While a personal timer runs, periodic server check-ins record connected working intervals to understand initial use and return visits.

Feedback is stored with the browser ID and, if supplied, an email address used only to reply. Feedback may be forwarded to the developer's inbox through the configured email provider. The database remains the record if email delivery fails.

The landing page also records page views, scroll depth, time on page and button clicks, referral codes and a country code inferred at the network edge. The app does not store your IP address as a user record; hosting providers process network requests.

What other people see

People in your room or Circle can see your chosen name, current study status and elapsed time, room goals, and messages you send. An invitation can show your name and completed time. Study progress sharing is off by default. If you turn it on, current members of your invited Circle can see your past and current study-time totals, daily and weekly graphs, and study-day heatmap. Materials, individual session details, and reply email are not included. You can change this choice when joining or later in Circle settings. Turning it off or leaving stops new access; information someone already viewed cannot be recalled. The choice and calendar time zone are stored on the server for that Circle.

Your device and service providers

Preferences, drafts and some study data also remain in this browser. Calendar files and share images are generated on your device. Cloudflare hosts the app and its database; Vercel hosts the landing page. Their infrastructure processes requests to deliver and protect the service. CoHours does not add advertising trackers, sell your data, or request camera or microphone access.

Using another device

Use the same Google account on each device to access your records and synchronize settings. You can use CoHours without signing in on a single browser. Google verifies your identity; CoHours stores a hash of the Google subject identifier, its link to your study records, and expiring session hashes in Cloudflare Durable Objects. Google tokens and passwords are not stored. A Google-linked identity requires a valid CoHours session. When signed in, your profile, material list and progress, goals, language and sound settings sync privately between your devices. Recurring session rules, reservations and cancellation exceptions use the same server records. Only a bounded current settings snapshot is stored; study history and active timers are not duplicated in it. Browser notification permission and unfinished drafts remain device-specific. Changes made offline are kept locally and retried when connected. Signing out revokes this device session; it does not delete records.

Questions and deletion requests

Use the app → Me → Feedback from the browser you use for CoHours, and say which data you want removed. The request includes this browser ID so its records can be located. You can also contact hello@cohours.com; we may need to confirm the browser ID. Requests are handled by the developer. Clearing browser storage does not delete server records, and may make it harder to connect your request to them. There is no automatic expiry currently promised for study records.

日本語

端末間で記録や設定を同期するには、それぞれの端末で同じGoogleアカウントを使います。一つのブラウザでは、ログインせずにCoHoursを利用できます。Googleの本人確認後、Google識別子のハッシュと学習記録との紐付け、有効期限付きのセッションのハッシュをCloudflare Durable Objectsに保存します。Googleのトークンやパスワードは保存しません。Googleに紐付けたIDには、有効なログインが必要です。Googleログイン中は、プロフィール・教材一覧と進捗・目標・言語・音の設定を、端末間で非公開のまま同期します。定期参加・予約・取消済みの回は、同じサーバーの記録を使います。設定は容量に上限を設けた最新の内容だけを保存し、学習履歴や動作中のタイマーは重複保存しません。ブラウザの通知許可と下書きは端末ごとに保持します。通信できない間の変更は端末に残し、接続回復後に再試行します。ログアウトはこの端末のセッションを無効にし、記録は削除しません。

ログインは不要です。ランダムなブラウザIDに学習時間、教材や目標、予約、在室、招待、Circleの活動、通知設定、基本的な利用イベントを結び付けてCloudflareに保存します。タイマー動作中の定期接続から、接続を確認できた学習時間も記録します。ブラウザIDの数は、確認済みの実人数とは限りません。

同じルームやCircleには名前、現在の学習状態と経過時間、送った目標やメッセージが見えます。学習グラフの共有は最初はオフです。オンにすると、同じ招待制Circleの現在のメンバーに、過去の記録を含む学習時間の合計、日別・週別グラフ、学習日のヒートマップが見えます。教材名、個々の学習内容、返信先メールは含みません。参加時と参加後のCircle設定で変更でき、オフにするか退出すると新たな閲覧を止めます。既に相手が見た情報を取り消すことはできません。共有の選択と集計のタイムゾーンはCircleごとにサーバーへ保存します。フィードバックと任意の返信先は保存し、返信先は返信だけに使います。削除依頼は利用中の端末からMe → フィードバックへ送ってください。ブラウザの保存内容を消してもサーバーの記録は消えません。開発者が個別に対応します。

Sincronización de cuenta

Al iniciar sesión con Google, tu perfil, materiales y progreso, objetivos, idioma y ajustes de sonido se sincronizan de forma privada entre dispositivos. Las reservas periódicas y cancelaciones usan los mismos registros del servidor. Solo se guarda una copia actual de los ajustes con un límite de tamaño; no se duplica el historial ni los temporizadores activos. Los permisos de notificaciones y los borradores pertenecen a cada dispositivo. Los cambios sin conexión se conservan localmente hasta poder sincronizarlos.

Compartir el progreso del Circle

La opción está desactivada al principio. Si la activas, los miembros actuales de tu Circle por invitación pueden ver tus totales de estudio anteriores y actuales, gráficos diarios y semanales, y el mapa de días de estudio. No se incluyen materiales, detalles de sesiones ni el correo de respuesta. Puedes elegir al unirte y cambiarlo después en los ajustes del Circle. Desactivarlo o salir impide nuevas consultas; no puede borrar lo que otra persona ya vio. La elección y la zona horaria se guardan en el servidor para ese Circle.