HaiFit

HaiFit is a free health and fitness companion app developed by Shenzhen Water World Software Technology Co., Ltd. for compatible budget smart bracelets and watches. After pairing your bracelet via Bluetooth, HaiFit acts as your health dashboard — displaying step counts, distance, calories burned, sleep analysis (deep and light sleep stages), heart rate, and other health metrics. It also forwards incoming call notifications (with caller name/number) and SMS messages (with sender name and content) from your phone to your bracelet. Additional features include sedentary reminders, smart alarms, step goals, cycling/running session records, and Apple Health integration on iOS. The app is free on both Android (Google Play, 500K+ downloads) and iOS (App Store).

To connect HaiFit to your phone: (1) Download HaiFit from the Google Play Store (package: com.waterworld.haifit) or Apple App Store (ID: 1567855547); (2) Open the app and register or log in; (3) Enable Bluetooth on your phone; (4) Power on your smart bracelet and place it in pairing mode; (5) In the HaiFit app, go to the device section and tap 'Add Device'; (6) Select your bracelet from the scan list and confirm the pairing; (7) Grant the app notification access permission when prompted. Once paired, HaiFit will continuously sync health data from your bracelet and forward notifications.

Common HaiFit connection issues and fixes: (1) Bluetooth disabled — ensure Bluetooth is on; force-close the app and restart it. (2) Out of range — keep phone and bracelet within 1–2 meters during initial pairing. (3) Cache issue — go to Settings > Apps > HaiFit > Storage, clear cache and data, then relaunch. (4) Outdated app — update HaiFit to the latest version from the Play Store or App Store. (5) Login loop — if you get 'invalid email/password' errors, try the password reset, or create a new account as some users report email verification issues. (6) Restart both devices — power off your phone and bracelet, then restart and re-pair. (7) Re-pair the device — remove the bracelet from the app and your phone's Bluetooth settings, then pair again from scratch.

HaiFit is designed for a range of budget smart bracelets and watches that ship with the HaiFit app as the companion software. Compatible devices include generic Chinese-brand models such as the Ultra 9, i8 Pro Max, and Series 8 smartwatches, among many other low-cost fitness trackers. If your smartwatch or bracelet's packaging includes a QR code pointing to HaiFit, or if the setup instructions specify 'download HaiFit,' this is the correct app for your device. There is no officially published full compatibility list — the app supports the specific hardware it ships with.

Yes. HaiFit integrates with Apple Health (HealthKit) on iOS devices. Once you authorize the connection in the app settings, HaiFit syncs your steps, calories, distance, and heart rate data to the Apple Health app, centralizing your fitness data alongside other health apps and devices. To enable: open HaiFit, go to settings, find the Apple Health option, and grant permission. Note that the Apple Health sync is an iOS-only feature.

HaiFit monitors your sleep data through your paired bracelet's sensors, recording total sleep duration and breaking it down into deep sleep and light sleep stages. To get accurate sleep data, wear your bracelet overnight and ensure it stays connected to your phone via Bluetooth. In the morning, open HaiFit to view your previous night's sleep summary including deep sleep duration, light sleep duration, and any awake periods detected. Weekly and monthly sleep trend views help identify patterns in your sleep habits over time.

Yes, HaiFit is completely free to download and use on both Android and iOS. There are no subscription fees, premium tiers, or in-app purchases. All features — health tracking, sleep monitoring, notifications, Apple Health sync, reminders, and device management — are available at no cost. The app generates revenue through the sale of compatible smartwatch hardware rather than app subscriptions.

HaiFit can track the following health metrics depending on your bracelet's hardware capabilities: daily steps, walking distance, calories burned, heart rate (real-time monitoring), sleep data (deep sleep and light sleep duration), blood oxygen saturation (SpO₂), blood pressure, blood glucose, and uric acid. Note that blood pressure, blood glucose, and uric acid readings require user calibration on supported devices, and all readings from consumer-grade bracelets are for general wellness reference only — not for medical diagnosis or treatment.

To enable call and message notifications on HaiFit: (1) Open the HaiFit app and ensure your bracelet is connected; (2) Go to device settings within the app; (3) Enable 'Incoming Call Reminder' — your bracelet will then vibrate and display the caller's name or phone number for incoming calls; (4) Enable 'SMS Reminder' to receive SMS notifications on your bracelet showing the sender's name and message content; (5) Grant HaiFit notification access permission in your phone's system settings if prompted. On Android, you may need to enable 'Notification Access' for HaiFit in Settings > Notifications > App Notifications.

HaiFit uses optical sensors in your budget smart bracelet to estimate health metrics. Inaccuracies are common due to: (1) Consumer-grade hardware — budget bracelets use lower-quality sensors than medical devices or premium smartwatches; (2) Wear position — the bracelet must be worn snugly on the wrist, about one finger-width above the wrist bone, for best accuracy; (3) Movement interference — readings taken during active movement may be less accurate than resting measurements; (4) Calibration — blood pressure, blood glucose, and uric acid readings require initial calibration in the app settings; (5) Individual variation — skin tone, circulation, and body composition can affect optical sensor accuracy. For medical concerns, always consult a healthcare professional and use certified medical devices.