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React Native

Identify devices in React Native apps through the native iOS and Android SDKs, with one TypeScript API and the same verdicts on both platforms.

@fingerly/react-native is a thin bridge to the native iOS and Android SDKs. Almost every signal worth having on a phone is out of reach of JavaScript, so the bridge calls native code rather than collecting less.

Requirements

  • React Native 0.74 or newer, including the New Architecture.
  • iOS 13 and Android 5.0 (API 21) or newer.
  • A development build. Expo Go cannot load native modules.

Install

npm install @fingerly/react-native
cd ios && pod install

Autolinking adds the native modules. Rebuild the app after installing.

Identify a device

fingerly.ts
import { load } from '@fingerly/react-native'

const fingerly = await load({ apiKey: 'fly_pk_us_production_…' })

export async function signIn(email: string, password: string) {
  const { requestId } = await fingerly.identify({ tag: 'sign-in' })
  return api.signIn({ email, password, requestId })
}

Send requestId to your backend with the action, and decide there after reading the stored event with a secret key. See server-side verification.

API

load(options)

  • apiKeystringrequired
    Your public key.
  • endpointstring
    A custom API origin or first-party proxy.
  • consent'granted' | 'pending' | 'denied'Default 'granted'
    Until it is granted, identify and collect read and send nothing and throw ConsentError. The state is shared by the whole app, so pass it on every load. See consent.

identify(options)

  • tagstring
    Your own reference for this identification.
  • submitbooleanDefault true
    Set false to collect without sending.

identify resolves with the same fields as the native SDKs: requestId, visitorId, visitorIsNew, visitorConfidence, identifiable, duplicate, state, suspectScore (number | null), suspectLevel, triggers, verdicts and report. collect() returns a report without submitting. setConsent(state) changes the consent state, and consent reads it.

Verdicts

VerdictPlatformWhat it means
instrumentationBothAn instrumentation toolkit is attached to the app.
mitmBothSomething is intercepting the app's encrypted traffic.
automationBothA debugger or a test runner is driving the app.
tamperingBothThe app's code has been hooked or modified.
farmBothThe device looks mass-provisioned or freshly reset.
jailbreak, simulatoriOSJailbroken device; iOS Simulator.
root, emulator, appClonerAndroidRooted device; emulator; cloning framework.

Verdicts a platform cannot answer are returned as { value: false, confidence: 'low', reasons: [] }, so the shape is the same on both.

Errors

errors.ts
import { FingerlyError } from '@fingerly/react-native'

try {
  await fingerly.identify()
} catch (error) {
  if (error instanceof FingerlyError && error.status === 401) {
    // the key is wrong or revoked
  }
}

Retries happen in the native layer. If the native module is missing, every call throws a FingerlyError that explains how to rebuild. Without consent, calls throw ConsentError, a FingerlyError whose code is consent_required.

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