@lokal-dev/react-native-device-metrics

Real-time device performance monitoring and telemetry for React Native. Collect CPU, memory, network, storage, and battery metrics with configurable thresholds and event-driven streaming.

Android only. This library does not support iOS.

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Features

• Real-time monitoring — Background collection at configurable intervals
• Two collection modes — Raw metrics only, or detailed (raw + performance levels per class)
• Metrics — CPU, memory, network, storage, battery
• Dual architecture — Old React Native bridge and TurboModule
• Event-driven — Real-time updates via DeviceEventEmitter
• TypeScript — Full type definitions
• Configurable thresholds — Tune performance classification (low / average / high / excellent)

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Requirements

Platform	Version / Notes
React Native CLI	0.73+
Expo (dev client)	SDK 50+ (not compatible with Expo Go)
Android	API 24+ (Android 7.0)
iOS	Not supported

Android

• minSdkVersion: 24
• compileSdkVersion: 35+

This library depends on a native Android SDK published to GitHub Packages. The Android build must have access to that Maven repository (see Installation).

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Installation

npm install @lokal-dev/react-native-device-metrics
# or
yarn add @lokal-dev/react-native-device-metrics

Linking is automatic. You still need to configure the GitHub Packages Maven repo so the Android dependency can be resolved.

GitHub Packages (Android)

Set these environment variables (token needs read:packages):

export GITHUB_USERNAME="your-github-username"
export GITHUB_TOKEN="your-github-personal-access-token"

React Native CLI

In your project’s project-level android/build.gradle:

allprojects {
    repositories {
        maven {
            url = uri("https://maven.pkg.github.com/lokal-app/device-telemetry-toolkit")
            credentials {
                username = System.getenv("GITHUB_USERNAME") ?: ""
                password = System.getenv("GITHUB_TOKEN") ?: ""
            }
        }
    }
}

Expo

Add the config plugin in app.json (it configures the Maven repo):

{
  "expo": {
    "plugins": ["@lokal-dev/react-native-device-metrics"]
  }
}

Then create a development build (Expo Go is not supported):

npx expo run:android

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Performance Classes & Levels

Classes (what you collect):

import { PerformanceClass } from '@lokal-dev/react-native-device-metrics';

PerformanceClass.CPU;     // 0
PerformanceClass.MEMORY;  // 1
PerformanceClass.STORAGE; // 2
PerformanceClass.NETWORK; // 3
PerformanceClass.BATTERY; // 4

Levels (classification result):

import { PerformanceLevel } from '@lokal-dev/react-native-device-metrics';

PerformanceLevel.UNKNOWN;  // 0
PerformanceLevel.LOW;      // 1
PerformanceLevel.AVERAGE; // 2
PerformanceLevel.HIGH;     // 3
PerformanceLevel.EXCELLENT;// 4

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Collection Flows

Two independent flows; both can run at the same time. Only shutdown() stops everything.

	Raw collection	Detailed collection
Data	Sensor/system values only	Raw + performanceLevel per class
Use case	Logging, custom logic	Ready-made performance assessment
Event	onRawPerformanceData	onDetailedPerformanceData
Overhead	Lower	Slightly higher (includes classification)

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Quick Start

1. Initialize

import * as DeviceMetrics from '@lokal-dev/react-native-device-metrics';

await DeviceMetrics.init();
// or with custom thresholds
await DeviceMetrics.init(customThresholds);

2. Raw data collection

// Start CPU + memory every 15s
await DeviceMetrics.startRawPerformanceDataCollection(
  [DeviceMetrics.PerformanceClass.CPU, DeviceMetrics.PerformanceClass.MEMORY],
  15
);

const subscription = DeviceMetrics.addRawPerformanceDataListener((data) => {
  console.log('CPU cores:', data.cpu?.coreCount);
  console.log('Available RAM:', data.memory?.availableRamGB, 'GB');
});

await DeviceMetrics.updateRawPerformanceDataCollection(10); // change interval
await DeviceMetrics.stopRawPerformanceDataCollection();
subscription.remove();

3. Detailed data collection

await DeviceMetrics.startDetailedPerformanceDataCollection(
  [DeviceMetrics.PerformanceClass.CPU, DeviceMetrics.PerformanceClass.MEMORY],
  15
);

const subscription = DeviceMetrics.addDetailedPerformanceDataListener((data) => {
  console.log('CPU level:', data.cpu?.performanceLevel);
  console.log('Memory level:', data.memory?.performanceLevel);
});

await DeviceMetrics.stopDetailedPerformanceDataCollection();
subscription.remove();

4. One-shot weighted assessment

const results = await DeviceMetrics.getWeightedPerformanceLevels([
  { class: DeviceMetrics.PerformanceClass.CPU, weight: 2.0 },
  { class: DeviceMetrics.PerformanceClass.MEMORY, weight: 1.5 },
  { class: DeviceMetrics.PerformanceClass.NETWORK, weight: 1.0 },
]);
console.log('Overall:', results.overallPerformanceLevel);
console.log('CPU:', results.cpu, 'Memory:', results.memory);

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API Reference

Initialization & lifecycle

Method	Description
init(thresholds?)	Initialize the SDK. Call before any other API.
shutdown()	Stop all flows and reset. Call init() again to reuse.

Raw collection

Method	Description
startRawPerformanceDataCollection(classes, delaySeconds)	Start periodic raw collection; emits onRawPerformanceData.
updateRawPerformanceDataCollection(delaySeconds)	Change interval; returns true if updated.
stopRawPerformanceDataCollection()	Stop raw collection only.
getLatestRawPerformanceData()	Last raw snapshot (parsed object, or null if none yet).
addRawPerformanceDataListener(callback)	Subscribe to raw events; returns EventSubscription.

Detailed collection

Method	Description
startDetailedPerformanceDataCollection(classes, delaySeconds)	Start detailed collection; emits onDetailedPerformanceData.
updateDetailedPerformanceDataCollection(delaySeconds)	Change interval; returns true if updated.
stopDetailedPerformanceDataCollection()	Stop detailed collection only.
getLatestDetailedPerformanceData()	Last detailed snapshot (parsed object, or null if none yet).
addDetailedPerformanceDataListener(callback)	Subscribe to detailed events; returns EventSubscription.

Performance levels

Method	Description
getWeightedPerformanceLevels(classesWithWeights)	One-shot weighted assessment. Returns a parsed WeightedPerformanceLevels object (overall + per-class levels as strings).
getPerformanceLevel(performanceClass)	Current performance level for one class. Returns a number: 0 (UNKNOWN), 1 (LOW), 2 (AVERAGE), 3 (HIGH), 4 (EXCELLENT).

Parameters

• classes: number[] — PerformanceClass values (CPU=0, MEMORY=1, STORAGE=2, NETWORK=3, BATTERY=4). Only these are collected; others are null in the result.
• delaySeconds: number — Interval in whole seconds (min 1).

Stop vs shutdown

• stopRawPerformanceDataCollection() / stopDetailedPerformanceDataCollection() — Stop that flow only; SDK stays initialized.
• shutdown() — Stop all flows and tear down the SDK.

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Custom Thresholds

Pass a thresholds object into init() to customize how raw values map to performance levels (e.g. memory, battery, CPU). See the type definitions for the full shape; example for memory and battery:

const customThresholds = {
  memory: {
    low: { approxHeapRemainingInMBThreshold: 32, approxHeapLimitInMBThreshold: 64 },
    average: { approxHeapRemainingInMBThreshold: 64, approxHeapLimitInMBThreshold: 128, availableRamGBThreshold: 1.5 },
    high: { approxHeapRemainingInMBThreshold: 256, availableRamGBThreshold: 3 },
  },
  battery: {
    excellent: { batteryPercentageThreshold: 80, isChargingBatteryPercentageThreshold: 70, temperatureThreshold: 30 },
    high: { batteryPercentageThreshold: 55, isChargingBatteryPercentageThreshold: 50, temperatureThreshold: 34 },
    average: { batteryPercentageThreshold: 40, isChargingBatteryPercentageThreshold: 35, temperatureThreshold: 38 },
  },
  // ... cpu, network, storage
};
await DeviceMetrics.init(customThresholds);

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Recommended Collection Intervals

Use case	Interval (seconds)
Background monitoring	15–30
Active feature monitoring	5–10
Call/video monitoring	2–5

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Troubleshooting

Build

• AGP / Kotlin version errors — Align Android Gradle Plugin and Kotlin versions with React Native 0.73+ (e.g. Kotlin 1.8.0+).

Runtime

• Cannot read property 'init' of undefined — Clean build and Metro cache:

  cd android && ./gradlew clean && cd ..
  npx react-native start --reset-cache

  Reinstall deps if needed: rm -rf node_modules && npm install.
• Collection never fires — Call await DeviceMetrics.init() before any start* method.

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Publishing

Manual release

1. Ensure you're logged in to npm: npm login
2. Commit all changes, clean working tree.
3. Build: yarn prepare
4. Bump: npm version patch (or minor / major)
5. Publish: npm publish --access public
6. Push: git push && git push --tags

Automated (release-it)

yarn release

This bumps version, tags, publishes to npm, and can create a GitHub release (if configured).

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Contributing

1. Fork the repo
2. Create a branch (git checkout -b feature/your-feature)
3. Commit (git commit -m 'feat: your change')
4. Push (git push origin feature/your-feature)
5. Open a Pull Request

See CONTRIBUTING.md and CODE_OF_CONDUCT.md.

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License

MIT — see LICENSE.

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Related

• device-telemetry-toolkit — Native Android performance SDK used by this library.

Built by Lokal.