README.md

add the plugin to your app config

// app.config.ts
[...]
plugins: {
		"./plugins/build/datadog-native-initialization.js",
		["expo-datadog"],
}
[...]

I do also run "eas-build-post-install": "bun run generate:datadog-config"

Main reason is we need the datadog config also in the expo-updates and to bundle the JS so we can't do that in the expo plugin at prebuild since the JS bundle is done before that in build steps on EAS.

In theory with this, datadog init before React-native. Hope it helps

datadog-native-initialization.ts

import { join, relative } from "node:path"
import {
	type ConfigPlugin,
	createRunOncePlugin,
	IOSConfig,
	withAppBuildGradle,
	withAppDelegate,
	withMainApplication,
	withXcodeProject,
} from "@expo/config-plugins"
import { addImports, findNewInstanceCodeBlock } from "@expo/config-plugins/build/android/codeMod"
import { insertContentsInsideSwiftFunctionBlock } from "@expo/config-plugins/build/ios/codeMod"
import { insertContentsAtOffset } from "@expo/config-plugins/build/utils/commonCodeMod"
import { mergeContents } from "@expo/config-plugins/build/utils/generateCode"

type DatadogConfig = {
	clientToken: string
	env: string
	applicationId: string
	nativeCrashReportEnabled: boolean
	nativeLongTaskThresholdMs?: number
	longTaskThresholdMs?: number
	sessionSamplingRate?: number
	site: "US1" | "US1_FED" | "US3" | "US5" | "EU1" | "AP1"
	trackingConsent?: "PENDING" | "GRANTED" | "NOT_GRANTED"
	telemetrySampleRate?: number
	vitalsUpdateFrequency?: "NEVER" | "RARE" | "AVERAGE" | "FREQUENT"
	uploadFrequency?: "RARE" | "AVERAGE" | "FREQUENT"
	batchSize?: "SMALL" | "MEDIUM" | "LARGE"
	trackFrustrations?: boolean
	trackBackgroundEvents?: boolean
	customEndpoints?: {
		rum?: string
		logs?: string
		trace?: string
	}
	nativeViewTracking?: boolean
	nativeInteractionTracking?: boolean
	verbosity?: "DEBUG" | "INFO" | "WARN" | "ERROR"
	proxy?: {
		type: "HTTP" | "HTTPS" | "SOCKS"
		address: string
		port: number
		username?: string
		password?: string
	}
	serviceName?: string
	version?: string
	firstPartyHosts?: Array<{
		match: string
		propagatorTypes?: Array<"DATADOG" | "B3" | "B3MULTI" | "TRACECONTEXT">
	}>
	trackInteractions: boolean
	trackResources: boolean
	trackErrors: boolean
	actionNameAttribute?: string
	useAccessibilityLabel?: boolean
	resourceTracingSamplingRate?: number
	bundleLogsWithRum?: boolean
	bundleLogsWithTraces?: boolean
	appHangThreshold?: number
	trackNonFatalAnrs?: boolean
	initialResourceThreshold?: number
}

/**
 * Adds Datadog native initialization to Android platform
 * This ensures Datadog SDK is initialized before React Native starts
 */
const withAndroidDatadogInit: ConfigPlugin = (config) => {
	return withMainApplication(config, async (config) => {
		// Add the import for Datadog native initialization
		config.modResults.contents = addImports(
			config.modResults.contents,
			["com.datadog.reactnative.DdSdkNativeInitialization"],
			false,
		)

		// Add the initialization call in onCreate() after super.onCreate()
		const initCall = "DdSdkNativeInitialization.initFromNative(this.applicationContext)\n"
		const res = findNewInstanceCodeBlock(config.modResults.contents, "onCreate", "kt")

		if (!config.modResults.contents.includes(initCall) && res) {
			const superOnCreateCall = "super.onCreate()"
			const index = res.code.indexOf(superOnCreateCall)

			if (index !== -1) {
				config.modResults.contents = insertContentsAtOffset(
					config.modResults.contents,
					initCall,
					res.start + index + superOnCreateCall.length + 1,
				)
			}
		}

		return config
	})
}

/**
 * Adds Datadog native initialization to iOS platform
 * This ensures Datadog SDK is initialized before React Native starts
 */
const withIOSDatadogInit: ConfigPlugin = (config) => {
	return withAppDelegate(config, (config) => {
		let contents = config.modResults.contents

		// Add the import for DatadogSDKReactNative
		contents = mergeContents({
			anchor: /import Expo/,
			comment: "//",
			newSrc: "import DatadogSDKReactNative",
			offset: 1,
			src: contents,
			tag: "ios-datadog-import",
		}).contents

		// Add the initialization call at the beginning of didFinishLaunchingWithOptions
		contents = insertContentsInsideSwiftFunctionBlock(
			contents,
			"application(_:didFinishLaunchingWithOptions:)",
			"DdSdk.initFromNative()",
			{ position: "head" },
		)

		config.modResults.contents = contents
		return config
	})
}

/**
 * Configures Android gradle to include Datadog configuration
 */
const withAndroidDatadogGradle: ConfigPlugin = (config) => {
	return withAppBuildGradle(config, (config) => {
		let contents = config.modResults.contents

		// Add the datadog configuration gradle script
		contents = mergeContents({
			anchor: /apply plugin: "com\.facebook\.react"/,
			comment: "//",
			newSrc: `apply from: "${config.modRequest.projectRoot}/node_modules/@datadog/mobile-react-native/datadog-configuration.gradle"`,
			offset: 1,
			src: contents,
			tag: "datadog-configuration-gradle",
		}).contents

		config.modResults.contents = contents
		return config
	})
}

/**
 * Configures iOS to include the Datadog configuration file as a resource
 */
const withIOSDatadogConfig: ConfigPlugin = (config) => {
	return withXcodeProject(config, (config) => {
		const projectRoot = config.modRequest.projectRoot
		const configFileName = "datadog-configuration.json"
		const configFilePath = join(projectRoot, configFileName)

		// Add the configuration file as a resource to the iOS project
		try {
			const relativePath = relative(config.modRequest.platformProjectRoot, configFilePath)
			IOSConfig.XcodeUtils.addResourceFileToGroup({
				filepath: relativePath,
				groupName: "Resources",
				isBuildFile: true,
				project: config.modResults,
				targetUuid: config.modResults.getFirstTarget().uuid,
				verbose: true,
			})
		} catch (error) {
			console.warn("Warning: Could not add datadog-configuration.json to iOS resources:", error)
		}

		return config
	})
}

/**
 * Main plugin that combines all Datadog native initialization features
 */
const withDatadogNativeInit: ConfigPlugin<DatadogConfig> = (c) => {
	let config = c

	// Configure Android
	config = withAndroidDatadogGradle(config)
	config = withAndroidDatadogInit(config)

	// Configure iOS
	config = withIOSDatadogConfig(config)
	config = withIOSDatadogInit(config)

	return config
}

export default createRunOncePlugin(withDatadogNativeInit, "DatadogNativeInitialization", "2.0.0")

generate-datadog-configuration.ts

import { writeFileSync } from "node:fs"
import { join } from "node:path"
import { Env } from "src/config/env"

const configFileName = "datadog-configuration.json"
const configFilePath = join(process.cwd(), configFileName)

if (!Env.DATADOG_CLIENT_TOKEN || !Env.DATADOG_RUM_APPLICATION_ID) {
	console.error("Datadog client token or RUM application ID is not set in environment variables.")
	process.exit(1)
}

const configContent: { configuration: DatadogConfig; $schema: string } = {
	$schema: "./node_modules/@datadog/mobile-react-native/datadog-configuration.schema.json",
	configuration: {
		applicationId: Env.DATADOG_RUM_APPLICATION_ID,
		batchSize: Env.IS_DEV ? "SMALL" : "MEDIUM",
		clientToken: Env.DATADOG_CLIENT_TOKEN,
		env: process.env.EXPO_PUBLIC_APP_VARIANT ?? "development",
		longTaskThresholdMs: 1000,
		nativeCrashReportEnabled: true,
		sessionSamplingRate: 100,
		site: "EU1",
		telemetrySampleRate: 20,
		trackBackgroundEvents: false,
		trackErrors: true,
		trackInteractions: false,
		// Ensure required fields are present with sensible defaults
		trackingConsent: "GRANTED",
		trackResources: false,
		uploadFrequency: Env.IS_DEV ? "FREQUENT" : "AVERAGE",
		verbosity: "WARN",
	},
}

console.log("Creating Datadog configuration file at:", configFilePath)
writeFileSync(configFilePath, JSON.stringify(configContent, null, 2))
console.log("Datadog configuration file created successfully.")

type DatadogConfig = {
	clientToken: string
	env: string
	applicationId: string
	nativeCrashReportEnabled: boolean
	nativeLongTaskThresholdMs?: number
	longTaskThresholdMs?: number
	sessionSamplingRate?: number
	site: "US1" | "US1_FED" | "US3" | "US5" | "EU1" | "AP1"
	trackingConsent?: "PENDING" | "GRANTED" | "NOT_GRANTED"
	telemetrySampleRate?: number
	vitalsUpdateFrequency?: "NEVER" | "RARE" | "AVERAGE" | "FREQUENT"
	uploadFrequency?: "RARE" | "AVERAGE" | "FREQUENT"
	batchSize?: "SMALL" | "MEDIUM" | "LARGE"
	trackFrustrations?: boolean
	trackBackgroundEvents?: boolean
	customEndpoints?: {
		rum?: string
		logs?: string
		trace?: string
	}
	nativeViewTracking?: boolean
	nativeInteractionTracking?: boolean
	verbosity?: "DEBUG" | "INFO" | "WARN" | "ERROR"
	proxy?: {
		type: "HTTP" | "HTTPS" | "SOCKS"
		address: string
		port: number
		username?: string
		password?: string
	}
	serviceName?: string
	version?: string
	firstPartyHosts?: Array<{
		match: string
		propagatorTypes?: Array<"DATADOG" | "B3" | "B3MULTI" | "TRACECONTEXT">
	}>
	trackInteractions: boolean
	trackResources: boolean
	trackErrors: boolean
	actionNameAttribute?: string
	useAccessibilityLabel?: boolean
	resourceTracingSamplingRate?: number
	bundleLogsWithRum?: boolean
	bundleLogsWithTraces?: boolean
	appHangThreshold?: number
	trackNonFatalAnrs?: boolean
	initialResourceThreshold?: number
}