# Zepp OS Developer Documentation

> Official API reference and guides for Zepp OS — the RTOS platform for wearable devices by Zepp Health. Covers Mini Program and Watchface development using JavaScript APIs (@zos/ui, @zos/sensor, @zos/ble, etc.), with a JS runtime on a C firmware layer.

Zepp OS exposes firmware capabilities through a JS framework layer. Developers use `@zos/*` module imports. The API is versioned by API_LEVEL (2.0, 3.0, 3.6, 4.0, 4.1, 4.2+), not OS version.

Key concepts:
- **Mini Program** (app) and **Watchface** are the two target types; some APIs are only available for one target
- **UI widgets** are created via `createWidget(widgetId, option)` and configured through property objects
- **Sensors** follow a start/stop/getCurrent/onChange pattern
- **Permission** system uses `device:os.*` codes; apps must declare them in `app.json`
- **File system** uses `@zos/fs` with sync/async variants; Mini Programs write to `/data` directory
- **BLE** uses `@zos/ble` for both peripheral and central roles

## Introduction

- [Introduction](https://docs.zepp.com/docs/intro/): What is Zepp OS
- [Version intro](https://docs.zepp.com/docs/intro/version/): Platform overview by version
- [What's new (4.2)](https://docs.zepp.com/docs/guides/version-info/new-features-42/): Latest API features
- [What's new (4.0)](https://docs.zepp.com/docs/guides/version-info/new-features-40/): API_LEVEL 4.0 additions
- [What's new (3.5)](https://docs.zepp.com/docs/guides/version-info/new-features-35/): API_LEVEL 3.5 additions
- [What's new (3.0)](https://docs.zepp.com/docs/guides/version-info/new-features-30/): API_LEVEL 3.0 additions
- [Zepp OS v2 features](https://docs.zepp.com/docs/guides/version-info/new-features/): v2.0 and v2.1 additions
- [New API in v2](https://docs.zepp.com/docs/guides/version-info/new-api/): API introduced in v2
- [Migration guide](https://docs.zepp.com/docs/guides/version-info/migration-guide/): Migrate between API versions
- [Version choose](https://docs.zepp.com/docs/guides/version-info/version-choose/): Which version to target

## Quick Start

- [Quick Start overview](https://docs.zepp.com/docs/guides/quick-start/): From zero to first build
- [Environment setup](https://docs.zepp.com/docs/guides/quick-start/environment/): Install tools and SDK
- [Create a project](https://docs.zepp.com/docs/guides/quick-start/create/): Scaffold your first app
- [Simulator development](https://docs.zepp.com/docs/guides/quick-start/simulator-dev/): Run in the simulator
- [Coding and debugging](https://docs.zepp.com/docs/guides/quick-start/development/): Debug workflow
- [Preview on watch](https://docs.zepp.com/docs/guides/quick-start/preview/): Push to real device

## Framework

### Device App (Mini Program)

- [Introduction](https://docs.zepp.com/docs/guides/framework/device/intro/): Mini Program architecture
- [JS support](https://docs.zepp.com/docs/guides/framework/device/js-support/): JavaScript runtime capabilities
- [App lifecycle](https://docs.zepp.com/docs/guides/framework/device/app/): App-level events
- [Page lifecycle](https://docs.zepp.com/docs/guides/framework/device/page/): Page lifecycle hooks
- [Secondary widget](https://docs.zepp.com/docs/guides/framework/device/secondary-widget/): Widget for watchface complication
- [Life cycle](https://docs.zepp.com/docs/guides/framework/device/life-cycle/): Page and app lifecycle reference
- [Router](https://docs.zepp.com/docs/guides/framework/device/router/): Navigation between pages
- [Compatibility](https://docs.zepp.com/docs/guides/framework/device/compatibility/): API_LEVEL system explained
- [Permission](https://docs.zepp.com/docs/guides/framework/device/permission/): Runtime permissions
- [File system](https://docs.zepp.com/docs/guides/framework/device/fs/): File operations
- [Screen adaptation](https://docs.zepp.com/docs/guides/framework/device/screen-adaption/): Multi-device layout
- [App Service](https://docs.zepp.com/docs/guides/framework/device/app-service/): Background services
- [System event](https://docs.zepp.com/docs/guides/framework/device/system-event/): System-level events
- [System notification](https://docs.zepp.com/docs/guides/framework/device/system-notification/): Notification API
- [BLE Central](https://docs.zepp.com/docs/guides/framework/device/ble-central/): Bluetooth Low Energy guide
- [Layout](https://docs.zepp.com/docs/guides/framework/device/layout/): Auto-layout system

### Settings App

- [Introduction](https://docs.zepp.com/docs/guides/framework/app-settings/intro/): Settings App overview
- [JS support](https://docs.zepp.com/docs/guides/framework/app-settings/js-support/): JavaScript capabilities
- [Register](https://docs.zepp.com/docs/guides/framework/app-settings/register/): How to register
- [UI introduction](https://docs.zepp.com/docs/guides/framework/app-settings/ui-intro/): Settings App UI

### Side Service

- [Introduction](https://docs.zepp.com/docs/guides/framework/side-service/intro/): Side Service overview
- [Register](https://docs.zepp.com/docs/guides/framework/side-service/register/): How to register

## Tools

- [Zeus CLI](https://docs.zepp.com/docs/guides/tools/cli/): Command-line tool
- [Simulator](https://docs.zepp.com/docs/guides/tools/simulator/): Device simulator
- [npm package](https://docs.zepp.com/docs/guides/tools/npm/): Package management
- [Zepp App](https://docs.zepp.com/docs/guides/tools/zepp-app/): Mobile companion app
- [Watchface Maker](https://docs.zepp.com/docs/guides/tools/watchface/): Visual watchface editor

## Device App API Reference (v3+ / @zos namespace)

Per-module enhanced references are available at `/llms/@zos-{module}.md`. Each module file contains the full API reference with constants, type signatures, and examples:

- [@zos/alarm](/llms/@zos-alarm.md) — Alarm API (set/cancel/getAllAlarms)
- [@zos/app](/llms/@zos-app.md) — Mini Program control (lifecycle, permissions, package info)
- [@zos/app-access](/llms/@zos-app-access.md) — App access (sport data)
- [@zos/app-service](/llms/@zos-app-service.md) — App service (background services)
- [@zos/ble](/llms/@zos-ble.md) — Bluetooth LE (peripheral + central roles)
- [@zos/device](/llms/@zos-device.md) — Device info
- [@zos/display](/llms/@zos-display.md) — Display control (brightness, settings)
- [@zos/fs](/llms/@zos-fs.md) — File system (sync read/write, sys properties)
- [@zos/global](/llms/@zos-global.md) — Global frame interfaces
- [@zos/i18n](/llms/@zos-i18n.md) — Internationalization
- [@zos/interaction](/llms/@zos-interaction.md) — Interaction (vibrate, screen resolution)
- [@zos/notification](/llms/@zos-notification.md) — Notification API
- [@zos/page](/llms/@zos-page.md) — Page data
- [@zos/router](/llms/@zos-router.md) — Router (page navigation)
- [@zos/sensor](/llms/@zos-sensor.md) — Sensors (accelerometer, heart rate, GPS, etc.)
- [@zos/settings](/llms/@zos-settings.md) — System settings (brightness, language, device info)
- [@zos/storage](/llms/@zos-storage.md) — Key-value storage
- [@zos/share-storage](/llms/@zos-share-storage.md) — Cross-application shared storage
- [@zos/timer](/llms/@zos-timer.md) — System timer
- [@zos/transfer-file](/llms/@zos-transfer-file.md) — File transfer
- [@zos/media](/llms/@zos-media.md) — Audio playback and recording
- [@zos/crypto](/llms/@zos-crypto.md) — Encryption, signatures, digests, and checksums
- [@zos/ui](/llms/@zos-ui.md) — UI overview and submodule index
- [@zos/ui-methods](/llms/@zos-ui-methods.md) — General UI methods, dialogs, keyboard, toast, layout helpers
- [@zos/ui-animations](/llms/@zos-ui-animations.md) — Widget animation APIs
- [@zos/ui-widget-basic](/llms/@zos-ui-widget-basic.md) — Basic widgets
- [@zos/ui-widget-form](/llms/@zos-ui-widget-form.md) — Form widgets
- [@zos/ui-widget-layout](/llms/@zos-ui-widget-layout.md) — Layout widgets
- [@zos/user](/llms/@zos-user.md) — User info
- [@zos/utils](/llms/@zos-utils.md) — Utilities (ASCII conversion, format)

### @zos/sensor — Sensors

- [Accelerometer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Accelerometer/): Device acceleration
- [Barometer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Barometer/): Atmospheric pressure
- [Battery](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Battery/): Battery level and charging
- [BloodOxygen](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/BloodOxygen/): SpO2 blood oxygen
- [BodyTemperature](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/BodyTemperature/): Body temperature
- [Buzzer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Buzzer/): Vibration patterns
- [Calorie](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Calorie/): Calorie data
- [Compass](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Compass/): Heading direction
- [Distance](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Distance/): Distance tracking
- [FatBurning](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/FatBurning/): Fat burn data
- [Geolocation](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Geolocation/): GPS positioning
- [Gyroscope](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Gyroscope/): Angular velocity
- [HeartRate](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/HeartRate/): Heart rate monitoring
- [Pai](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Pai/): PAI activity score
- [Screen](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Screen/): Screen on/off state
- [Sleep](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Sleep/): Sleep tracking
- [Stand](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Stand/): Stand detection
- [Step](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Step/): Step counter
- [Stress](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Stress/): Stress level
- [SystemSounds](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/SystemSounds/): System sound playback
- [Time](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Time/): Time and date
- [Vibrator](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Vibrator/): Vibration motor
- [Wear](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Wear/): Wear detection
- [Weather](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Weather/): Weather data
- [Workout](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/Workout/): Workout tracking
- [WorldClock](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/WorldClock/): World clock zones
- [checkSensor](https://docs.zepp.com/docs/reference/device-app-api/newAPI/sensor/checkSensor/): Check sensor availability

### @zos/app — Mini Program App Control (Mini Program only)

- [startApp](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/startApp/): Start another Mini Program
- [gotoPage](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/gotoPage/): Navigate to page
- [reloadPage](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/reloadPage/): Reload current page
- [setLayerY](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/setLayerY/): Set layer Y offset
- [getLayerY](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/getLayerY/): Get layer Y offset
- [gotoHome](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/gotoHome/): Go to home screen
- [exit](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/exit/): Exit app
- [goBack](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/goBack/): Go back
- [setScreenKeep](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/setScreenKeep/): Keep screen on
- [getPackageInfo](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/getPackageInfo/): Get package info
- [getPackageInfoById](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/getPackageInfoById/): Get package info by ID
- [getPerformance](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/getPerformance/): Get performance data
- [getScene](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/getScene/): Get current scene
- [queryPermission](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/queryPermission/): Query permission status
- [requestPermission](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/requestPermission/): Request permissions
- [emitCustomSystemEvent](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app/emitCustomSystemEvent/): Emit custom system event

### @zos/app-service — App Service (Mini Program only)

- [start](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app-service/start/): Start app service
- [stop](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app-service/stop/): Stop app service
- [getAllAppServices](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app-service/getAllAppServices/): List all services
- [exit](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app-service/exit/): Exit service

### @zos/app-access — App Access (Mini Program only)

- [getSportData](https://docs.zepp.com/docs/reference/device-app-api/newAPI/app-access/getSportData/): Get sport/health data

### @zos/ble — Bluetooth Low Energy (Mini Program only)

- [createConnect](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/createConnect/): Create BLE connection
- [connectStatus](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/connectStatus/): Check connection status
- [addListener](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/addListener/): Listen for BLE events
- [removeListener](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/removeListener/): Remove BLE listener
- [send](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/send/): Send data
- [mstStartScan](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/mstStartScan/): Start central scan
- [mstConnect](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/mstConnect/): Central mode connect
- [mstDisconnect](https://docs.zepp.com/docs/reference/device-app-api/newAPI/ble/mstDisconnect/): Central mode disconnect
- Full central/master API: getProfileInstance, buildProfile, readCharacteristic, writeCharacteristic, etc.

### @zos/fs — File System

- [statSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/statSync/): Get file info
- [rmSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/rmSync/): Delete file
- [renameSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/renameSync/): Rename file
- [openSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/openSync/): Open file sync
- [closeSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/closeSync/): Close file
- [readSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/readSync/): Read file
- [writeSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/writeSync/): Write file
- [seekSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/seekSync/): Seek in file
- [statAssetSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/statAssetSync/): Get asset file info
- [openAssetSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/fs/openAssetSync/): Open asset file
- System Properties: SysProSetBool, SysProGetBool, SysProSetInt, SysProGetInt, SysProSetInt64, SysProGetInt64, SysProSetDouble, SysProGetDouble, SysProSetChars, SysProGetChars

### @zos/settings — System Settings

- [setScreenAutoBright](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/setScreenAutoBright/): Auto brightness
- [getBrightness](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/getBrightness/): Get brightness
- [getDeviceInfo](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/getDeviceInfo/): Device info
- [getUserData](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/getUserData/): User data
- [getLanguage](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/getLanguage/): Get language
- [getScreenType](https://docs.zepp.com/docs/reference/device-app-api/newAPI/settings/getScreenType/): Screen type (round/rect)

### @zos/device — Device Info

- [getDeviceInfo](https://docs.zepp.com/docs/reference/device-app-api/newAPI/device/getDeviceInfo/): Device information
- [getDiskInfo](https://docs.zepp.com/docs/reference/device-app-api/newAPI/device/getDiskInfo/): Disk space info

### @zos/display — Display Control

- [getBrightness](https://docs.zepp.com/docs/reference/device-app-api/newAPI/display/getBrightness/): Get brightness
- [getAutoBrightness](https://docs.zepp.com/docs/reference/device-app-api/newAPI/display/getAutoBrightness/): Auto brightness
- [getSettings](https://docs.zepp.com/docs/reference/device-app-api/newAPI/display/getSettings/): Display settings

### @zos/i18n — Internationalization

- [getLanguage](https://docs.zepp.com/docs/reference/device-app-api/newAPI/i18n/getLanguage/): Get language
- [getLocale](https://docs.zepp.com/docs/reference/device-app-api/newAPI/i18n/getLocale/): Get locale

### @zos/interaction — Interaction

- [vibrate](https://docs.zepp.com/docs/reference/device-app-api/newAPI/interaction/vibrate/): Trigger vibration
- [getDesignResolutionWidth](https://docs.zepp.com/docs/reference/device-app-api/newAPI/interaction/getDesignResolutionWidth/): Get design width
- [getDesignResolutionHeight](https://docs.zepp.com/docs/reference/device-app-api/newAPI/interaction/getDesignResolutionHeight/): Get design height

### @zos/timer — System Timer

- [createTimer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/timer/createTimer/): Create timer
- [stopTimer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/timer/stopTimer/): Stop timer

### @zos/storage — Storage

- [getSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/storage/getSync/): Read storage
- [setSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/storage/setSync/): Write storage
- [deleteSync](https://docs.zepp.com/docs/reference/device-app-api/newAPI/storage/deleteSync/): Delete storage entry

### @zos/alarm — Alarm (Mini Program only)

- [set](https://docs.zepp.com/docs/reference/device-app-api/newAPI/alarm/set/): Set alarm
- [cancel](https://docs.zepp.com/docs/reference/device-app-api/newAPI/alarm/cancel/): Cancel alarm
- [getAllAlarms](https://docs.zepp.com/docs/reference/device-app-api/newAPI/alarm/getAllAlarms/): List all alarms

### @zos/notification — Notification (Mini Program only)

- [notify](https://docs.zepp.com/docs/reference/device-app-api/newAPI/notification/notify/): Send notification

### @zos/page — Page Module

- [getPageData](https://docs.zepp.com/docs/reference/device-app-api/newAPI/page/getPageData/): Get page data
- [setPageData](https://docs.zepp.com/docs/reference/device-app-api/newAPI/page/setPageData/): Set page data

### @zos/router — Router Module

- [replace](https://docs.zepp.com/docs/reference/device-app-api/newAPI/router/replace/): Replace page

### @zos/user — User Info

- [getUserInfo](https://docs.zepp.com/docs/reference/device-app-api/newAPI/user/getUserInfo/): Get user info

### @zos/transfer-file — File Transfer

- [transferFile](https://docs.zepp.com/docs/reference/device-app-api/newAPI/transfer-file/transferFile/): Transfer file to side service

### @zos/utils — Utilities

- [EventBus](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/EventBus/): Event publish/subscribe utility
- [assets](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/assets/): Resource path helper
- [bufferToString](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/bufferToString/): Convert `ArrayBuffer` to string
- [log](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/log/): Structured logging helpers
- [px](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/px/): Pixel scaling helper
- [stringToBuffer](https://docs.zepp.com/docs/reference/device-app-api/newAPI/utils/stringToBuffer/): Convert string to `ArrayBuffer`

### Global API

- [Global](https://docs.zepp.com/docs/reference/device-app-api/newAPI/global/): Frame-level global interfaces

## Watchface API

- [Watchface Quick Start](https://docs.zepp.com/docs/watchface/watchface-quick-start/): Build your first watchface
- [Watchface app.json](https://docs.zepp.com/docs/watchface/app-json/): Watchface configuration
- [Watchface API reference](https://docs.zepp.com/docs/watchface/api/): Full watchface API (uses hmUI/hmSensor/hmFS/hmSetting/hmBle with some differences from Mini Program)
- [Watchface specification](https://docs.zepp.com/docs/watchface/specification/): Design specifications
- [Watchface design resources](https://docs.zepp.com/docs/watchface/design-resources/): Asset templates

## Settings App API

- [Global](https://docs.zepp.com/docs/reference/app-settings-api/global/): Settings App global API
- [UI Components](https://docs.zepp.com/docs/reference/app-settings-api/ui/): Settings App UI sections, links, text
- [Settings Storage](https://docs.zepp.com/docs/reference/app-settings-api/settings-storage/): Persistent key-value storage

## Side Service API

- [Global](https://docs.zepp.com/docs/reference/side-service-api/global/): Side Service global API
- [Messaging](https://docs.zepp.com/docs/reference/side-service-api/messaging/): Communicate with device
- [Fetch](https://docs.zepp.com/docs/reference/side-service-api/fetch/): HTTP requests
- [Settings Storage](https://docs.zepp.com/docs/reference/side-service-api/settings-storage/): Server-side storage
- [Transfer File](https://docs.zepp.com/docs/reference/side-service-api/transfer-file/): Send files
- [Download File](https://docs.zepp.com/docs/reference/side-service-api/download-file/): Download files
- [Image Convert](https://docs.zepp.com/docs/reference/side-service-api/image-convert/): Convert images

## Best Practices

- [Debug](https://docs.zepp.com/docs/guides/best-practice/debug/): Debugging techniques
- [Multi-screen adaptation](https://docs.zepp.com/docs/guides/best-practice/multi-screen-adaption/): Support multiple devices
- [Code adaptation for new devices](https://docs.zepp.com/docs/guides/best-practice/code-adaptations-for-new-devices/): Porting guide
- [Code organization](https://docs.zepp.com/docs/guides/best-practice/code-organization/): Project structure tips
- [Cross-page communication](https://docs.zepp.com/docs/guides/best-practice/cross-page-communications/): Page-to-page data flow
- [BLE communication](https://docs.zepp.com/docs/guides/best-practice/bluetooth-communication/): Bluetooth best practices
- [Widget group](https://docs.zepp.com/docs/guides/best-practice/widget-group/): Organizing UI widgets
- [Persistent storage](https://docs.zepp.com/docs/guides/best-practice/persistence-storage/): Data persistence
- [Error handling](https://docs.zepp.com/docs/guides/best-practice/error-catch/): Error catching patterns
- [Internationalization](https://docs.zepp.com/docs/guides/best-practice/i18n/): i18n best practices

## TypeScript Definitions

- [@zos/* type declarations on npm](https://www.npmjs.com/package/@zeppos/device-api-typings): Official TypeScript types — the most accurate source for module signatures, parameter types, and return values

## Reference

- [app.json configuration](https://docs.zepp.com/docs/reference/app-json/): Full app manifest spec
- [Device list](https://docs.zepp.com/docs/reference/related-resources/device-list/): Supported devices and screen specs
- [Design resources](https://docs.zepp.com/docs/reference/related-resources/design-resources/): UI design templates and specs
- [Physical keys](https://docs.zepp.com/docs/reference/related-resources/physical-keys/): Hardware key mappings
- [Language list](https://docs.zepp.com/docs/reference/related-resources/language-list/): Supported languages and i18n codes
- [Revision history](https://docs.zepp.com/docs/reference/revision-history/): API changelog

## FAQ

- [Watchface Maker](https://docs.zepp.com/docs/guides/faq/watchface-maker/): Watchface Maker FAQ
- [Icon FAQ](https://docs.zepp.com/docs/guides/faq/icon-faq/): App icon requirements
- [Simulator FAQ](https://docs.zepp.com/docs/guides/faq/simulator-faq/): Common simulator issues
- [Bridge mode](https://docs.zepp.com/docs/guides/faq/developer-bridge-mode/): Developer bridge mode setup
- [Environment setup](https://docs.zepp.com/docs/guides/faq/env-setup/): Environment troubleshooting
- [Upload logs](https://docs.zepp.com/docs/guides/faq/upload-log/): How to upload logs
- [Paid apps](https://docs.zepp.com/docs/guides/faq/paid-app/): Paid app distribution