Privacy Policy

Knotos ("chúng tôi") là ứng dụng nhắn tin và gọi điện realtime được phát triển bởi Van Thuong Dao. This Privacy Policy explains what personal data we collect when you use the Knotos iOS app and website (knotos.io.vn), how we use it, and your rights regarding that data.

When you create an account and use Knotos, we collect:

• Phone number — used as your unique identifier for login and contact discovery.
• Display name and profile photo — shown to other users in conversations.
• Username — optional public handle for discovery.
• Messages and media — text messages, images, videos, audio notes, and files you send or receive.
• Call records — caller, recipient, duration, and timestamp of voice and video calls.
• Device push token (APNs) — used to deliver push notifications to your device.
• IP address and approximate location — collected during connection for fraud prevention.
• App usage data — feature interactions, crash reports, and performance logs used to improve the app.

We do not collect payment information, precise GPS location, or contacts without your explicit permission.

• Providing core app features: sending messages, making calls, managing chats.
• Authenticating your identity when you log in.
• Delivering push notifications for new messages and calls.
• Enabling contact discovery so others can find you by phone number.
• Detecting and preventing abuse, spam, and fraud.
• Diagnosing technical issues and improving app performance.

We do not sell, rent, or trade your personal data. We share data only in limited circumstances:

• Other users — your display name, profile photo, and online status are visible to users you communicate with.
• Infrastructure providers — cloud hosting and object storage providers process data on our behalf under strict confidentiality agreements.
• Legal obligations — we may disclose data if required by applicable Vietnamese law or a valid court order.

We never share your data for advertising purposes.

Your data is retained as long as your account is active. When you delete your account:

• Your profile, messages, and media are permanently deleted within 30 days.
• Call records are deleted immediately.
• Anonymised aggregate statistics may be retained for service improvement.

We protect your data using industry-standard measures: passwords are hashed with bcrypt, data is transmitted over TLS/HTTPS, and access to production systems is restricted. Voice and video calls use WebRTC with encrypted signalling. No security system is perfect — we encourage you to use a strong, unique password and keep your device up to date.

You have the right to:

• Access — request a copy of the personal data we hold about you.
• Correction — ask us to correct inaccurate data.
• Deletion — delete your account and all associated data via Settings → Account → Delete Account.
• Portability — request your data in a machine-readable format.
• Objection — opt out of non-essential data processing.

To exercise any of these rights, email us at vanthuong.dao2004@gmail.com.

Knotos is not directed at children under 13. We do not knowingly collect personal data from anyone under 13. If you believe a child has provided us with personal information, please contact us immediately and we will delete it.

We may update this policy as the app evolves. Material changes will be notified via in-app notification or email at least 14 days before taking effect.

Questions or requests regarding this policy:

• Email: vanthuong.dao2004@gmail.com
• Website: https://knotos.io.vn/support