Effective date: July 20, 2026
N4x4 is built to respect your privacy. There is no account, no sign-up, and no advertising. In plain terms: your training data stays with you.
None is sent to us. N4x4 has no analytics SDK, no ad network, and no server that receives your personal information. Everything the app records lives on your device.
With your permission, N4x4 reads and writes data in Apple Health (HealthKit), such as your workouts, heart rate, and VO₂ max, so it can show your trends and save completed sessions. This data stays on your device and in Apple Health under your control. N4x4 does not transmit your Health data anywhere, and Apple prohibits using it for advertising. You can revoke access at any time in the iPhone Settings app under Privacy & Security → Health.
If you connect a Bluetooth heart rate monitor (for example a chest strap, Garmin watch, or WHOOP), N4x4 uses Bluetooth only to receive your live heart rate during a workout. That reading is used on your device and is not sent to us.
Your saved sessions, interval charts, and any notes you add are stored locally on your device. They are included in your device backups if you have them enabled, and are not uploaded to N4x4.
When you tap "Submit Feedback," your mail app opens a message to us. It may include your app version, iOS version, and device model so we can help. Sending it is entirely your choice, and we use anything you send only to respond to you.
The website is hosted on standard web infrastructure that keeps basic server logs (such as IP address and time of visit) for security and reliability. The site embeds a YouTube video using the privacy-enhanced (no-cookie) player; if you play it, YouTube's own policies apply.
N4x4 is not directed at children under 13 and does not knowingly collect information from them.
We may update this policy from time to time. Changes take effect when posted here, with the effective date above updated. Please review it periodically.
Questions about privacy? Email support@n4x4.app.