diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 1a45798f9..f85ddba42 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -12,6 +12,8 @@ plugins {
     alias(libs.plugins.ksp)
     alias(libs.plugins.hilt.android)
     alias(libs.plugins.compose.compiler)
+    alias(libs.plugins.google.services)
+    alias(libs.plugins.firebase.crashlytics)
 }
 
 android {
@@ -43,8 +45,16 @@ android {
 
     buildTypes {
         debug {
+            applicationIdSuffix = ".debug"
+            versionNameSuffix = "-debug"
             buildConfigField("String", "BASE_URL", "\"${localProperties["base_url"] ?: ""}\"")
         }
+        create("qa") {
+            initWith(getByName("debug"))
+            applicationIdSuffix = ".qa"
+            versionNameSuffix = "-qa"
+            matchingFallbacks += listOf("debug")
+        }
         release {
             buildConfigField("String", "BASE_URL", "\"${localProperties["base_url"] ?: ""}\"")
 
@@ -67,9 +77,6 @@ android {
         buildConfig = true
         viewBinding = true
     }
-    composeOptions {
-        kotlinCompilerExtensionVersion = "1.5.1"
-    }
     packaging {
         resources {
             excludes += "/META-INF/{AL2.0,LGPL2.1}"
@@ -125,6 +132,11 @@ dependencies {
     debugImplementation(libs.androidx.ui.tooling)
     debugImplementation(libs.androidx.ui.test.manifest)
 
+    implementation(platform(libs.firebase.bom))
+    implementation(libs.firebase.config.ktx)
+    implementation(libs.firebase.analytics.ktx)
+    implementation(libs.firebase.crashlytics.ktx)
+
     implementation(libs.play.services.auth)
     implementation(libs.androidx.credentials)
     implementation(libs.androidx.credentials.play.services.auth)
diff --git a/app/src/main/java/com/umc/edison/EdisonApplication.kt b/app/src/main/java/com/umc/edison/EdisonApplication.kt
index 419f0d357..06f579acc 100644
--- a/app/src/main/java/com/umc/edison/EdisonApplication.kt
+++ b/app/src/main/java/com/umc/edison/EdisonApplication.kt
@@ -3,18 +3,44 @@ package com.umc.edison
 import android.app.Application
 import android.util.Log
 import androidx.work.Configuration
+import com.google.firebase.ktx.Firebase
+import com.google.firebase.remoteconfig.FirebaseRemoteConfigSettings
+import com.google.firebase.remoteconfig.ktx.remoteConfig
+import com.umc.edison.common.logging.AppLogger
 import com.umc.edison.data.di.EntryPointModule
 import com.umc.edison.data.sync.SyncDataWorkerFactory
 import com.umc.edison.presentation.sync.SyncTrigger
+import com.umc.edison.remote.config.DomainProvider
 import dagger.hilt.EntryPoints
 import dagger.hilt.android.HiltAndroidApp
 import io.branch.referral.Branch
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.tasks.await
+import javax.inject.Inject
+import com.umc.edison.common.logging.UserContext
+import com.umc.edison.remote.config.RemoteConfigKeys
 
 @HiltAndroidApp
 class EdisonApplication : Application(), Configuration.Provider {
+    @Inject
+    lateinit var domainProvider: DomainProvider
+
+    @Inject
+    lateinit var userContext: UserContext
+
+    private val remoteConfigScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private val remoteConfig by lazy { Firebase.remoteConfig }
+    private val maxAttempts = 4
+    private val initialBackoffMs = 1_000L
 
     override fun onCreate() {
         super.onCreate()
+        initCrashlyticsContext()
+        initRemoteConfig()
 
         // Branch SDK 초기화
         Branch.getAutoInstance(this)
@@ -24,6 +50,61 @@ class EdisonApplication : Application(), Configuration.Provider {
         syncTrigger.setupSync()
     }
 
+    private fun initCrashlyticsContext() {
+        remoteConfigScope.launch {
+            userContext.ensureInstallId()
+            userContext.setBuildInfo(
+                BuildConfig.BUILD_TYPE,
+                BuildConfig.APPLICATION_ID,
+                BuildConfig.VERSION_NAME
+            )
+        }
+    }
+
+    private fun initRemoteConfig() {
+
+        val settings = FirebaseRemoteConfigSettings.Builder()
+            .setMinimumFetchIntervalInSeconds(if (BuildConfig.DEBUG) 0 else 60 * 60 * 12)
+            .build()
+        remoteConfig.setConfigSettingsAsync(settings)
+
+        remoteConfig.setDefaultsAsync(
+            mapOf(RemoteConfigKeys.BASE_URL to BuildConfig.BASE_URL)
+        )
+
+        remoteConfig.getString(RemoteConfigKeys.BASE_URL)
+            .takeIf { it.isNotBlank() }
+            ?.let(domainProvider::setDomain)
+
+        remoteConfigScope.launch {
+            var backoff = initialBackoffMs
+            repeat(maxAttempts) { attempt ->
+                val activated = try {
+                    remoteConfig.fetchAndActivate().await()
+                } catch (e: Exception) {
+                    AppLogger.w(
+                        "EdisonApplication",
+                        "Remote config fetch failed on attempt ${attempt + 1}",
+                        e
+                    )
+                    false
+                }
+
+                if (activated) {
+                    remoteConfig.getString(RemoteConfigKeys.BASE_URL)
+                        .takeIf { it.isNotBlank() }
+                        ?.let(domainProvider::setDomain)
+                    return@launch
+                }
+
+                if (attempt < maxAttempts - 1) {
+                    delay(backoff)
+                    backoff = (backoff * 2).coerceAtMost(8_000L)
+                }
+            }
+        }
+    }
+
     override val workManagerConfiguration: Configuration
         get() {
             val syncDataWorkerFactory: SyncDataWorkerFactory = EntryPoints.get(
diff --git a/app/src/main/java/com/umc/edison/common/logging/AppLogger.kt b/app/src/main/java/com/umc/edison/common/logging/AppLogger.kt
new file mode 100644
index 000000000..560c59239
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/common/logging/AppLogger.kt
@@ -0,0 +1,36 @@
+package com.umc.edison.common.logging
+
+import android.util.Log
+import com.google.firebase.crashlytics.ktx.crashlytics
+import com.google.firebase.ktx.Firebase
+import com.umc.edison.BuildConfig
+
+object AppLogger {
+    private const val PREFIX_DEBUG = "D/"
+    private const val PREFIX_INFO = "I/"
+    private const val PREFIX_WARN = "W/"
+    private const val PREFIX_ERROR = "E/"
+    private val isDebug = BuildConfig.DEBUG
+
+    fun d(tag: String, message: String) {
+        if (isDebug) Log.d(tag, message)
+        Firebase.crashlytics.log("$PREFIX_DEBUG$tag: $message")
+    }
+
+    fun i(tag: String, message: String) {
+        if (isDebug) Log.i(tag, message)
+        Firebase.crashlytics.log("$PREFIX_INFO$tag: $message")
+    }
+
+    fun w(tag: String, message: String, throwable: Throwable? = null) {
+        if (isDebug) Log.w(tag, message, throwable)
+        Firebase.crashlytics.log("$PREFIX_WARN$tag: $message")
+        throwable?.let { Firebase.crashlytics.recordException(it) }
+    }
+
+    fun e(tag: String, message: String, throwable: Throwable? = null) {
+        if (isDebug) Log.e(tag, message, throwable)
+        Firebase.crashlytics.log("$PREFIX_ERROR$tag: $message")
+        throwable?.let { Firebase.crashlytics.recordException(it) }
+    }
+}
diff --git a/app/src/main/java/com/umc/edison/common/logging/UserContext.kt b/app/src/main/java/com/umc/edison/common/logging/UserContext.kt
new file mode 100644
index 000000000..8990fcd2d
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/common/logging/UserContext.kt
@@ -0,0 +1,39 @@
+package com.umc.edison.common.logging
+
+import com.google.firebase.crashlytics.ktx.crashlytics
+import com.google.firebase.ktx.Firebase
+import com.umc.edison.data.datasources.PrefDataSource
+import java.util.UUID
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class UserContext @Inject constructor(
+    private val prefDataSource: PrefDataSource
+) {
+    companion object {
+        private const val KEY_INSTALL_ID = "install_id"
+    }
+
+    suspend fun ensureInstallId(): String {
+        val existing: String = prefDataSource.get(KEY_INSTALL_ID, "")
+        if (existing.isNotBlank()) {
+            Firebase.crashlytics.setCustomKey(KEY_INSTALL_ID, existing)
+            return existing
+        }
+        val newId = UUID.randomUUID().toString()
+        prefDataSource.set(KEY_INSTALL_ID, newId)
+        Firebase.crashlytics.setCustomKey(KEY_INSTALL_ID, newId)
+        return newId
+    }
+
+    fun setAccountId(accountId: String) {
+        Firebase.crashlytics.setUserId(accountId)
+    }
+
+    fun setBuildInfo(buildType: String, applicationId: String, versionName: String) {
+        Firebase.crashlytics.setCustomKey("build_type", buildType)
+        Firebase.crashlytics.setCustomKey("application_id", applicationId)
+        Firebase.crashlytics.setCustomKey("version_name", versionName)
+    }
+}
diff --git a/app/src/main/java/com/umc/edison/data/model/user/UserEntity.kt b/app/src/main/java/com/umc/edison/data/model/user/UserEntity.kt
index 5b6251268..b57379283 100644
--- a/app/src/main/java/com/umc/edison/data/model/user/UserEntity.kt
+++ b/app/src/main/java/com/umc/edison/data/model/user/UserEntity.kt
@@ -4,12 +4,14 @@ import com.umc.edison.data.model.DataMapper
 import com.umc.edison.domain.model.user.User
 
 data class UserEntity(
+    val id: Long? = null,
     val nickname: String?,
     val profileImage: String?,
     val email: String
 ) : DataMapper<User> {
     override fun toDomain(): User {
         return User(
+            id = id,
             nickname = nickname,
             profileImage = profileImage,
             email = email
@@ -19,6 +21,7 @@ data class UserEntity(
 
 fun User.toData(): UserEntity {
     return UserEntity(
+        id = id,
         nickname = nickname,
         profileImage = profileImage,
         email = email
diff --git a/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt b/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
index 615de050b..f2ff3203b 100644
--- a/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
+++ b/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
@@ -1,12 +1,12 @@
 package com.umc.edison.data.repository
 
-import android.util.Log
 import com.umc.edison.data.bound.FlowBoundResourceFactory
 import com.umc.edison.data.datasources.BubbleLocalDataSource
 import com.umc.edison.data.datasources.BubbleRemoteDataSource
 import com.umc.edison.data.model.bubble.ClusteredBubbleEntity
 import com.umc.edison.data.model.bubble.KeywordBubbleEntity
 import com.umc.edison.data.model.bubble.toData
+import com.umc.edison.common.logging.AppLogger
 import com.umc.edison.domain.DataResource
 import com.umc.edison.domain.model.bubble.Bubble
 import com.umc.edison.domain.model.bubble.ClusteredBubble
@@ -77,7 +77,7 @@ class BubbleRepositoryImpl @Inject constructor(
                         )
                     } catch (e: Exception) {
                         // 로컬에 없는 버블은 무시
-                        Log.d("BubbleRepositoryImpl", "getAllClusteredBubbles: ${e.message}")
+                        AppLogger.d("BubbleRepositoryImpl", "getAllClusteredBubbles: ${e.message}")
                     }
                 }
 
@@ -99,7 +99,7 @@ class BubbleRepositoryImpl @Inject constructor(
                         )
                     } catch (e: Exception) {
                         // 로컬에 없는 버블은 무시
-                        Log.d("BubbleRepositoryImpl", "getKeywordBubbles: ${e.message}")
+                        AppLogger.d("BubbleRepositoryImpl", "getKeywordBubbles: ${e.message}")
                         null
                     }
                 }
diff --git a/app/src/main/java/com/umc/edison/data/repository/SyncRepositoryImpl.kt b/app/src/main/java/com/umc/edison/data/repository/SyncRepositoryImpl.kt
index fc61668b2..6575b2143 100644
--- a/app/src/main/java/com/umc/edison/data/repository/SyncRepositoryImpl.kt
+++ b/app/src/main/java/com/umc/edison/data/repository/SyncRepositoryImpl.kt
@@ -1,6 +1,6 @@
 package com.umc.edison.data.repository
 
-import android.util.Log
+import com.umc.edison.common.logging.AppLogger
 import com.umc.edison.data.datasources.BubbleLocalDataSource
 import com.umc.edison.data.datasources.BubbleRemoteDataSource
 import com.umc.edison.data.datasources.LabelLocalDataSource
@@ -15,7 +15,7 @@ class SyncRepositoryImpl @Inject constructor(
      private val labelLocalDataSource: LabelLocalDataSource,
 ) : SyncRepository {
     override suspend fun syncLocalDataToServer() {
-        Log.i("syncLocalDataToServer", "syncLocalDataToServer is started")
+        AppLogger.i("syncLocalDataToServer", "syncLocalDataToServer is started")
 
         val unSyncedLabels = labelLocalDataSource.getUnSyncedLabels()
         unSyncedLabels.forEach { label ->
@@ -23,7 +23,7 @@ class SyncRepositoryImpl @Inject constructor(
             if (syncedLabel.same(label)) {
                 labelLocalDataSource.markAsSynced(syncedLabel)
             } else {
-                Log.e("syncLocalDataToServer", "Failed to sync label: ${label.id}")
+                AppLogger.e("syncLocalDataToServer", "Failed to sync label: ${label.id}")
             }
         }
 
@@ -33,13 +33,13 @@ class SyncRepositoryImpl @Inject constructor(
             if (syncedBubble.same(bubble)) {
                 bubbleLocalDataSource.markAsSynced(bubble)
             } else {
-                Log.e("syncLocalDataToServer", "Failed to sync bubble: ${bubble.id}")
+                AppLogger.e("syncLocalDataToServer", "Failed to sync bubble: ${bubble.id}")
             }
         }
     }
 
     override suspend fun syncServerDataToLocal() {
-        Log.i("syncServerDataToLocal", "syncServerDataToLocal is started")
+        AppLogger.i("syncServerDataToLocal", "syncServerDataToLocal is started")
         val remoteLabels = labelRemoteDataSource.getAllLabels()
         labelLocalDataSource.syncLabels(remoteLabels)
 
diff --git a/app/src/main/java/com/umc/edison/data/token/AccessTokenProvider.kt b/app/src/main/java/com/umc/edison/data/token/AccessTokenProvider.kt
index 3d86a8878..f795277fa 100644
--- a/app/src/main/java/com/umc/edison/data/token/AccessTokenProvider.kt
+++ b/app/src/main/java/com/umc/edison/data/token/AccessTokenProvider.kt
@@ -3,6 +3,6 @@ package com.umc.edison.data.token
 interface AccessTokenProvider {
     fun getAccessToken(): String?
     fun getRefreshToken(): String?
-    fun clearCachedTokens()
-    fun setCachedTokens(accessToken: String, refreshToken: String?)
-}
\ No newline at end of file
+    suspend fun clearCachedTokens()
+    suspend fun setCachedTokens(accessToken: String, refreshToken: String?)
+}
diff --git a/app/src/main/java/com/umc/edison/data/token/DefaultTokenRetryHandler.kt b/app/src/main/java/com/umc/edison/data/token/DefaultTokenRetryHandler.kt
index 16c1cdcc3..270e6f203 100644
--- a/app/src/main/java/com/umc/edison/data/token/DefaultTokenRetryHandler.kt
+++ b/app/src/main/java/com/umc/edison/data/token/DefaultTokenRetryHandler.kt
@@ -3,6 +3,7 @@ package com.umc.edison.data.token
 import com.google.android.gms.common.api.ApiException
 import com.umc.edison.data.datasources.UserRemoteDataSource
 import javax.inject.Inject
+import retrofit2.HttpException
 
 class DefaultTokenRetryHandler @Inject constructor(
     private val userRemoteDataSource: UserRemoteDataSource,
@@ -12,10 +13,10 @@ class DefaultTokenRetryHandler @Inject constructor(
     override suspend fun <T> runWithTokenRetry(dataAction: suspend () -> T): T {
         return try {
             dataAction()
-        } catch (e: ApiException) {
-            if (e.message != "LOGIN4004") throw e
+        } catch (e: Throwable) {
+            if (!isUnauthorized(e)) throw e
 
-            val refreshToken = tokenManager.loadRefreshToken() ?: throw IllegalStateException("No refresh token")
+            val refreshToken = tokenManager.loadRefreshToken() ?: throw NoRefreshTokenException()
 
             val newAccessToken = userRemoteDataSource.refreshAccessToken(refreshToken)
             tokenManager.setToken(newAccessToken, refreshToken)
@@ -23,4 +24,9 @@ class DefaultTokenRetryHandler @Inject constructor(
             dataAction()
         }
     }
+
+    private fun isUnauthorized(e: Throwable): Boolean {
+        return (e is ApiException && e.message == "LOGIN4004") ||
+                (e is HttpException && e.code() == 401)
+    }
 }
diff --git a/app/src/main/java/com/umc/edison/data/token/TokenExceptions.kt b/app/src/main/java/com/umc/edison/data/token/TokenExceptions.kt
new file mode 100644
index 000000000..21a73e02c
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/data/token/TokenExceptions.kt
@@ -0,0 +1,4 @@
+package com.umc.edison.data.token
+
+class NoRefreshTokenException : IllegalStateException("No refresh token")
+class RefreshFailedException(message: String) : IllegalStateException(message)
diff --git a/app/src/main/java/com/umc/edison/data/token/TokenManager.kt b/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
index 7c8987ca6..2f5f0a186 100644
--- a/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
+++ b/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
@@ -1,11 +1,13 @@
 package com.umc.edison.data.token
 
-import javax.inject.Inject
-import javax.inject.Singleton
 import com.umc.edison.data.datasources.PrefDataSource
 import com.umc.edison.data.di.ApplicationScope
+import javax.inject.Inject
+import javax.inject.Singleton
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 
 @Singleton
 class TokenManager @Inject constructor(
@@ -13,68 +15,76 @@ class TokenManager @Inject constructor(
     @ApplicationScope private val applicationScope: CoroutineScope
 ) : AccessTokenProvider {
 
-    init {
-        applicationScope.launch {
-            loadAccessToken()
-            loadRefreshToken()
-        }
-    }
+    private val mutex = Mutex()
 
     private var cachedAccessToken: String? = null
     private var cachedRefreshToken: String? = null
 
-    override fun getAccessToken(): String? {
-        if (cachedAccessToken == null) {
-            println("⚠️ Warning: access token not cached. Consider calling loadAccessToken() at app startup.")
+    init {
+        applicationScope.launch {
+            preloadTokens()
         }
-        return cachedAccessToken
     }
 
-    override fun getRefreshToken(): String? {
-        if (cachedRefreshToken == null) {
-            println("⚠️ Warning: refresh token not cached. Consider calling loadRefreshToken() at app startup.")
-        }
-        return cachedRefreshToken
-    }
+    override fun getAccessToken(): String? = cachedAccessToken
 
-    override fun clearCachedTokens() {
-        cachedAccessToken = null
-        cachedRefreshToken = null
+    override fun getRefreshToken(): String? = cachedRefreshToken
+
+    override suspend fun clearCachedTokens() {
+        mutex.withLock {
+            cachedAccessToken = null
+            cachedRefreshToken = null
+        }
     }
 
-    override fun setCachedTokens(accessToken: String, refreshToken: String?) {
-        cachedAccessToken = accessToken
-        cachedRefreshToken = refreshToken
+    override suspend fun setCachedTokens(accessToken: String, refreshToken: String?) {
+        mutex.withLock {
+            cachedAccessToken = accessToken
+            cachedRefreshToken = refreshToken
+        }
     }
 
     suspend fun loadAccessToken(): String? {
-        val token = prefDataSource.get(ACCESS_TOKEN_KEY, "")
-        cachedAccessToken = token.ifEmpty { null }
-
-        return token
+        return mutex.withLock {
+            val token = prefDataSource.get(ACCESS_TOKEN_KEY, "")
+            cachedAccessToken = token.ifEmpty { null }
+            token
+        }
     }
 
     suspend fun loadRefreshToken(): String? {
-        val token = prefDataSource.get(REFRESH_TOKEN_KEY, "")
-        cachedRefreshToken = token.ifEmpty { null }
-
-        return token
+        return mutex.withLock {
+            val token = prefDataSource.get(REFRESH_TOKEN_KEY, "")
+            cachedRefreshToken = token.ifEmpty { null }
+            token
+        }
     }
 
     suspend fun setToken(accessToken: String, refreshToken: String? = null) {
-        cachedAccessToken = accessToken
-        prefDataSource.set(ACCESS_TOKEN_KEY, accessToken)
-        refreshToken?.let {
-            prefDataSource.set(REFRESH_TOKEN_KEY, it)
-            cachedRefreshToken = it
+        mutex.withLock {
+            cachedAccessToken = accessToken
+            prefDataSource.set(ACCESS_TOKEN_KEY, accessToken)
+            refreshToken?.let {
+                prefDataSource.set(REFRESH_TOKEN_KEY, it)
+                cachedRefreshToken = it
+            }
         }
     }
 
     suspend fun deleteToken() {
-        cachedAccessToken = null
-        cachedRefreshToken = null
-        prefDataSource.remove(ACCESS_TOKEN_KEY)
-        prefDataSource.remove(REFRESH_TOKEN_KEY)
+        mutex.withLock {
+            cachedAccessToken = null
+            cachedRefreshToken = null
+            prefDataSource.remove(ACCESS_TOKEN_KEY)
+            prefDataSource.remove(REFRESH_TOKEN_KEY)
+        }
+    }
+
+    private suspend fun preloadTokens() {
+        mutex.withLock {
+            cachedAccessToken = prefDataSource.get(ACCESS_TOKEN_KEY, "").ifEmpty { null }
+            cachedRefreshToken = prefDataSource.get(REFRESH_TOKEN_KEY, "").ifEmpty { null }
+        }
     }
 
     companion object {
diff --git a/app/src/main/java/com/umc/edison/domain/model/user/User.kt b/app/src/main/java/com/umc/edison/domain/model/user/User.kt
index f3a76c53b..057674cf9 100644
--- a/app/src/main/java/com/umc/edison/domain/model/user/User.kt
+++ b/app/src/main/java/com/umc/edison/domain/model/user/User.kt
@@ -1,6 +1,7 @@
 package com.umc.edison.domain.model.user
 
 data class User(
+    val id: Long?,
     val nickname: String?,
     val profileImage: String?,
     val email: String
diff --git a/app/src/main/java/com/umc/edison/presentation/base/BaseViewModel.kt b/app/src/main/java/com/umc/edison/presentation/base/BaseViewModel.kt
index a0dabf193..4279645e8 100644
--- a/app/src/main/java/com/umc/edison/presentation/base/BaseViewModel.kt
+++ b/app/src/main/java/com/umc/edison/presentation/base/BaseViewModel.kt
@@ -1,8 +1,8 @@
 package com.umc.edison.presentation.base
 
-import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.umc.edison.common.logging.AppLogger
 import com.umc.edison.domain.DataResource
 import com.umc.edison.presentation.ToastManager
 import kotlinx.coroutines.flow.Flow
@@ -31,7 +31,7 @@ open class BaseViewModel @Inject constructor(
     ) {
         viewModelScope.launch {
             flow.onCompletion {
-                Log.d("collectDataResource", "onComplete")
+                AppLogger.d("collectDataResource", "onComplete")
                 _baseState.update {
                     it.copy(isLoading = false)
                 }
@@ -39,12 +39,12 @@ open class BaseViewModel @Inject constructor(
             }.collect { dataResource ->
                 when (dataResource) {
                     is DataResource.Success -> {
-                        Log.d("collectDataResource", "onSuccess: ${dataResource.data}")
+                        AppLogger.d("collectDataResource", "onSuccess: ${dataResource.data}")
                         onSuccess(dataResource.data)
                     }
 
                     is DataResource.Error -> {
-                        Log.e("collectDataResource", "onError: ${dataResource.throwable}")
+                        AppLogger.e("collectDataResource", "onError: ${dataResource.throwable}", dataResource.throwable)
                         _baseState.update {
                             it.copy(error = dataResource.throwable)
                         }
@@ -52,7 +52,7 @@ open class BaseViewModel @Inject constructor(
                     }
 
                     is DataResource.Loading -> {
-                        Log.d("collectDataResource", "onLoading")
+                        AppLogger.d("collectDataResource", "onLoading")
                         _baseState.update {
                             it.copy(isLoading = true)
                         }
diff --git a/app/src/main/java/com/umc/edison/presentation/login/GoogleLoginHelper.kt b/app/src/main/java/com/umc/edison/presentation/login/GoogleLoginHelper.kt
index 02245bf7e..6ff6ed07e 100644
--- a/app/src/main/java/com/umc/edison/presentation/login/GoogleLoginHelper.kt
+++ b/app/src/main/java/com/umc/edison/presentation/login/GoogleLoginHelper.kt
@@ -1,7 +1,6 @@
 package com.umc.edison.presentation.login
 
 import android.content.Context
-import android.util.Log
 import androidx.credentials.CredentialManager
 import androidx.credentials.CustomCredential
 import androidx.credentials.GetCredentialRequest
@@ -11,6 +10,8 @@ import com.google.android.libraries.identity.googleid.GetGoogleIdOption
 import com.google.android.libraries.identity.googleid.GoogleIdTokenCredential
 import com.umc.edison.BuildConfig
 import com.umc.edison.R
+import com.umc.edison.common.logging.AppLogger
+import com.umc.edison.common.logging.UserContext
 import com.umc.edison.domain.DataResource
 import com.umc.edison.domain.usecase.user.GoogleLoginUseCase
 import com.umc.edison.domain.usecase.sync.SyncServerDataToLocalUseCase
@@ -28,6 +29,7 @@ class GoogleLoginHelper @Inject constructor(
     private val googleLoginUseCase: GoogleLoginUseCase,
     private val syncLocalDataToServerUseCase: SyncLocalDataToServerUseCase,
     private val syncServerDataToLocalUseCase: SyncServerDataToLocalUseCase,
+    private val userContext: UserContext,
 ) {
     private val coroutineScope = MainScope()
 
@@ -75,7 +77,7 @@ class GoogleLoginHelper @Inject constructor(
             is GoogleIdTokenCredential -> {
                 val idToken = credential.idToken
                 if (BuildConfig.DEBUG){
-                    Log.d("Google SignIn", "ID Token: $idToken")
+                    AppLogger.d("Google SignIn", "ID Token: $idToken")
                 }
 
                 sendIdTokenToServer(idToken, onResult)
@@ -88,11 +90,11 @@ class GoogleLoginHelper @Inject constructor(
                             GoogleIdTokenCredential.createFrom(credential.data)
                         val idToken = googleIdTokenCredential.idToken
                         if (BuildConfig.DEBUG){
-                            Log.d("Google SignIn", "ID Token (CustomCredential): $idToken")
+                            AppLogger.d("Google SignIn", "ID Token (CustomCredential): $idToken")
                         }
                         sendIdTokenToServer(idToken, onResult)
                     } catch (e: Exception) {
-                        Log.e("Google SignIn", "Received an invalid Google ID token response", e)
+                        AppLogger.e("Google SignIn", "Received an invalid Google ID token response", e)
                         onResult(GoogleLoginState.Failure(GoogleLoginState.ERROR_MESSAGE_INVALID_TOKEN))
                     }
                 } else {
@@ -115,32 +117,34 @@ class GoogleLoginHelper @Inject constructor(
                 when (result) {
                     is DataResource.Success -> {
                         onResult(GoogleLoginState.Success(result.data.toPresentation()))
+                        // Crashlytics user 식별자 설정
+                        result.data.id?.let { userContext.setAccountId(it.toString()) }
 
                         try {
                             syncLocalDataToServerUseCase()
                         } catch (e: Throwable) {
-                            Log.e("Init sync local to server data", "Failed to sync data", e)
+                            AppLogger.e("Init sync local to server data", "Failed to sync data", e)
                         }
 
                         try {
                             syncServerDataToLocalUseCase()
                         } catch (e: Throwable) {
-                            Log.e("Init sync server to local data", "Failed to sync data", e)
+                            AppLogger.e("Init sync server to local data", "Failed to sync data", e)
                         }
                     }
 
                     is DataResource.Error -> {
                         val t = result.throwable
-                        Log.e("Google SignIn", "로그인 실패", t)
+                        AppLogger.e("Google SignIn", "로그인 실패", t)
                         val errorCode = (t as? HttpException)?.let { exception ->
                             exception.response()?.errorBody()?.string()?.also { errorBody ->
-                                Log.e("Google SignIn", "errorBody: $errorBody")
+                                AppLogger.e("Google SignIn", "errorBody: $errorBody")
                             }?.let { errorBody ->
                                 runCatching {
                                     JSONObject(errorBody).optString("code")
                                         .takeIf { it.isNotEmpty() }
                                 }
-                                    .onFailure { Log.e("Google SignIn", "에러 바디 파싱 실패", it) }
+                                    .onFailure { AppLogger.e("Google SignIn", "에러 바디 파싱 실패", it) }
                                     .getOrNull()
                             }
                         }
diff --git a/app/src/main/java/com/umc/edison/presentation/model/UserModel.kt b/app/src/main/java/com/umc/edison/presentation/model/UserModel.kt
index 6586bc3bf..c082c2926 100644
--- a/app/src/main/java/com/umc/edison/presentation/model/UserModel.kt
+++ b/app/src/main/java/com/umc/edison/presentation/model/UserModel.kt
@@ -17,6 +17,7 @@ data class UserModel(
 
     fun toDomain(): User {
         return User(
+            id = null,
             nickname = nickname,
             profileImage = profileImage,
             email = email,
diff --git a/app/src/main/java/com/umc/edison/remote/api/RefreshTokenApiService.kt b/app/src/main/java/com/umc/edison/remote/api/RefreshTokenApiService.kt
index 1fd10ff24..2f7f88b29 100644
--- a/app/src/main/java/com/umc/edison/remote/api/RefreshTokenApiService.kt
+++ b/app/src/main/java/com/umc/edison/remote/api/RefreshTokenApiService.kt
@@ -7,5 +7,5 @@ import retrofit2.http.POST
 
 interface RefreshTokenApiService {
     @POST("members/refresh")
-    fun refreshToken(@Header("Refresh-Token") refreshToken: String): ResponseWithData<RefreshTokenResponse>
+    suspend fun refreshToken(@Header("Refresh-Token") refreshToken: String): ResponseWithData<RefreshTokenResponse>
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/umc/edison/remote/config/DomainProvider.kt b/app/src/main/java/com/umc/edison/remote/config/DomainProvider.kt
new file mode 100644
index 000000000..aa1a57d99
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/remote/config/DomainProvider.kt
@@ -0,0 +1,18 @@
+package com.umc.edison.remote.config
+
+import com.umc.edison.BuildConfig
+import javax.inject.Inject
+import javax.inject.Singleton
+import kotlin.concurrent.Volatile
+
+@Singleton
+class DomainProvider @Inject constructor() {
+    @Volatile private var current: String = BuildConfig.BASE_URL
+
+    fun getDomain(): String = current
+    fun setDomain(domain: String) {
+        if (domain.isNotBlank() && domain != current) {
+            current = domain
+        }
+    }
+}
diff --git a/app/src/main/java/com/umc/edison/remote/config/RemoteConfigKeys.kt b/app/src/main/java/com/umc/edison/remote/config/RemoteConfigKeys.kt
new file mode 100644
index 000000000..ceb97d787
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/remote/config/RemoteConfigKeys.kt
@@ -0,0 +1,13 @@
+package com.umc.edison.remote.config
+
+object RemoteConfigKeys {
+    /**
+     * API Base URL
+     */
+    const val BASE_URL = "base_url"
+
+    /**
+     * Branch SDK Key
+     */
+    const val BRANCH_KEY = "branch_key"
+}
diff --git a/app/src/main/java/com/umc/edison/remote/datasources/UserRemoteDataSourceImpl.kt b/app/src/main/java/com/umc/edison/remote/datasources/UserRemoteDataSourceImpl.kt
index 0006e1026..e4f109248 100644
--- a/app/src/main/java/com/umc/edison/remote/datasources/UserRemoteDataSourceImpl.kt
+++ b/app/src/main/java/com/umc/edison/remote/datasources/UserRemoteDataSourceImpl.kt
@@ -14,6 +14,7 @@ import com.umc.edison.remote.model.login.toSetIdentityKeywordRequest
 import com.umc.edison.remote.model.mypage.toUpdateTestRequest
 import com.umc.edison.remote.model.mypage.toUpdateProfileRequest
 import com.umc.edison.remote.api.RefreshTokenApiService
+import com.umc.edison.data.token.RefreshFailedException
 import com.umc.edison.remote.model.login.SignUpRequest
 import javax.inject.Inject
 
@@ -59,7 +60,11 @@ class UserRemoteDataSourceImpl @Inject constructor(
     }
 
     override suspend fun refreshAccessToken(refreshToken: String): String {
-        return refreshTokenApiService.refreshToken(refreshToken).data.accessToken
+        val response = refreshTokenApiService.refreshToken(refreshToken)
+        if (!response.isSuccess) {
+            throw RefreshFailedException("Refresh token failed: ${response.code}")
+        }
+        return response.data.accessToken
     }
 
     // READ
diff --git a/app/src/main/java/com/umc/edison/remote/di/NetworkModule.kt b/app/src/main/java/com/umc/edison/remote/di/NetworkModule.kt
index 2ae54265d..13453adc3 100644
--- a/app/src/main/java/com/umc/edison/remote/di/NetworkModule.kt
+++ b/app/src/main/java/com/umc/edison/remote/di/NetworkModule.kt
@@ -3,6 +3,7 @@ package com.umc.edison.remote.di
 import com.umc.edison.BuildConfig
 import com.umc.edison.remote.token.AccessTokenInterceptor
 import com.umc.edison.data.token.TokenManager
+import com.umc.edison.remote.interceptor.HostSelectionInterceptor
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
@@ -50,10 +51,12 @@ object NetworkModule {
     fun provideOkHttpClient(
         httpLoggingInterceptor: HttpLoggingInterceptor,
         accessTokenInterceptor: AccessTokenInterceptor,
+        hostSelectionInterceptor: HostSelectionInterceptor,
     ) : OkHttpClient = OkHttpClient.Builder()
         .connectTimeout(TIME_OUT.toLong(), TimeUnit.SECONDS)
         .readTimeout(TIME_OUT.toLong(), TimeUnit.SECONDS)
         .writeTimeout(TIME_OUT.toLong(), TimeUnit.SECONDS)
+        .addInterceptor(hostSelectionInterceptor)
         .addInterceptor(httpLoggingInterceptor)
         .addInterceptor(accessTokenInterceptor)
         .build()
diff --git a/app/src/main/java/com/umc/edison/remote/interceptor/HostSelectionInterceptor.kt b/app/src/main/java/com/umc/edison/remote/interceptor/HostSelectionInterceptor.kt
new file mode 100644
index 000000000..dd1eea777
--- /dev/null
+++ b/app/src/main/java/com/umc/edison/remote/interceptor/HostSelectionInterceptor.kt
@@ -0,0 +1,28 @@
+package com.umc.edison.remote.interceptor
+
+import com.umc.edison.remote.config.DomainProvider
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import okhttp3.Interceptor
+import okhttp3.Response
+import javax.inject.Inject
+
+class HostSelectionInterceptor @Inject constructor(
+    private val domainProvider: DomainProvider
+) : Interceptor {
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val originalRequest = chain.request()
+        val base = domainProvider.getDomain().toHttpUrlOrNull()
+        val newReq = base?.let {
+            val newUrl = originalRequest.url.newBuilder()
+                .scheme(it.scheme)
+                .host(it.host)
+                .port(it.port)
+                .build()
+
+            originalRequest.newBuilder()
+                .url(newUrl)
+                .build()
+        } ?: originalRequest
+        return chain.proceed(newReq)
+    }
+}
diff --git a/app/src/main/java/com/umc/edison/remote/model/login/LoginResponse.kt b/app/src/main/java/com/umc/edison/remote/model/login/LoginResponse.kt
index 19286e565..ac33d93db 100644
--- a/app/src/main/java/com/umc/edison/remote/model/login/LoginResponse.kt
+++ b/app/src/main/java/com/umc/edison/remote/model/login/LoginResponse.kt
@@ -26,6 +26,7 @@ data class LoginResponse(
 
     fun toUserEntity(): UserEntity =
         UserEntity(
+            id = memberId,
             nickname = nickname,
             profileImage = null,
             email = email
diff --git a/app/src/main/java/com/umc/edison/remote/model/login/SignUpResponse.kt b/app/src/main/java/com/umc/edison/remote/model/login/SignUpResponse.kt
index 46eb1957b..9fb1e09b2 100644
--- a/app/src/main/java/com/umc/edison/remote/model/login/SignUpResponse.kt
+++ b/app/src/main/java/com/umc/edison/remote/model/login/SignUpResponse.kt
@@ -27,6 +27,7 @@ data class SignUpResponse(
 
     fun toUserEntity(): UserEntity =
         UserEntity(
+            id = memberId,
             nickname = nickname,
             profileImage = null,
             email = email
diff --git a/app/src/main/java/com/umc/edison/remote/token/AccessTokenInterceptor.kt b/app/src/main/java/com/umc/edison/remote/token/AccessTokenInterceptor.kt
index 438fa2824..1f4497cea 100644
--- a/app/src/main/java/com/umc/edison/remote/token/AccessTokenInterceptor.kt
+++ b/app/src/main/java/com/umc/edison/remote/token/AccessTokenInterceptor.kt
@@ -1,5 +1,6 @@
 package com.umc.edison.remote.token
 
+import com.umc.edison.common.logging.AppLogger
 import com.umc.edison.data.token.AccessTokenProvider
 import okhttp3.Interceptor
 import okhttp3.Response
@@ -19,6 +20,8 @@ class AccessTokenInterceptor @Inject constructor(
         val requestBuilder = chain.request().newBuilder()
         if (!token.isNullOrEmpty()) {
             requestBuilder.addHeader(HEADER_AUTHORIZATION, "$TOKEN_TYPE $token")
+        } else {
+            AppLogger.w("AccessTokenInterceptor", "Access token missing, sending request without Authorization header")
         }
 
         return chain.proceed(requestBuilder.build())
diff --git a/app/src/main/java/com/umc/edison/ui/artboard/ArtLetterDetailScreen.kt b/app/src/main/java/com/umc/edison/ui/artboard/ArtLetterDetailScreen.kt
index a962bea69..83795e366 100644
--- a/app/src/main/java/com/umc/edison/ui/artboard/ArtLetterDetailScreen.kt
+++ b/app/src/main/java/com/umc/edison/ui/artboard/ArtLetterDetailScreen.kt
@@ -1,7 +1,6 @@
 package com.umc.edison.ui.artboard
 
 import android.content.Intent
-import android.util.Log
 import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.animateFloat
 import androidx.compose.animation.core.infiniteRepeatable
@@ -68,6 +67,7 @@ import com.umc.edison.ui.theme.Gray300
 import com.umc.edison.ui.theme.Gray500
 import com.umc.edison.ui.theme.Gray600
 import com.umc.edison.ui.theme.Gray800
+import com.umc.edison.common.logging.AppLogger
 import io.branch.indexing.BranchUniversalObject
 import io.branch.referral.util.ContentMetadata
 import io.branch.referral.util.LinkProperties
@@ -247,7 +247,7 @@ fun ArtLetterDetailScreen(
                                             val shareIntent = Intent.createChooser(sendIntent, null)
                                             context.startActivity(shareIntent)
                                         } else {
-                                            Log.e("BranchShare", "Branch error: ${error.message}")
+                                            AppLogger.e("BranchShare", "Branch error: ${error.message}")
                                         }
                                     }
                                 },
diff --git a/app/src/main/java/com/umc/edison/ui/components/ImageGallery.kt b/app/src/main/java/com/umc/edison/ui/components/ImageGallery.kt
index a962af40c..072604e15 100644
--- a/app/src/main/java/com/umc/edison/ui/components/ImageGallery.kt
+++ b/app/src/main/java/com/umc/edison/ui/components/ImageGallery.kt
@@ -5,7 +5,7 @@ import android.content.Context
 import android.net.Uri
 import android.os.Build
 import android.provider.MediaStore
-import android.util.Log
+import com.umc.edison.common.logging.AppLogger
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.background
@@ -249,7 +249,7 @@ fun loadGalleryImages(context: Context, folder: String): List<Uri> {
             val name = it.getString(nameColumn)
             val contentUri = ContentUris.withAppendedId(uriExternal, id)
 
-            Log.d("GalleryImage", "Image: $name, URI: $contentUri")
+            AppLogger.d("GalleryImage", "Image: $name, URI: $contentUri")
             images.add(contentUri)
         }
     }
diff --git a/build.gradle.kts b/build.gradle.kts
index 03cd1a9dc..6b63fa7c0 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -5,4 +5,6 @@ plugins {
     alias(libs.plugins.ksp) apply false
     alias(libs.plugins.hilt.android)  apply false
     alias(libs.plugins.compose.compiler) apply false
+    alias(libs.plugins.google.services) apply false
+    alias(libs.plugins.firebase.crashlytics) apply false
 }
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 832feea83..fee3e716a 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -26,12 +26,16 @@ okhttp = "4.12.0"
 retrofit = "2.10.0"
 gson = "2.10.1"
 coil = "3.0.1"
-hilt = "2.51.1"
+hilt = "2.57.1"
 hiltCommon = "1.2.0"
 work = "2.10.2"
 foundationLayoutAndroid = "1.8.3"
 foundationAndroid = "1.8.3"
 hiltWork = "1.2.0"
+firebaseBom = "33.1.0"
+googleServices = "4.4.4"
+crashlytics = "18.6.2"
+crashlyticsPlugin = "3.0.2"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -83,10 +87,16 @@ androidx-foundation-layout-android = { group = "androidx.compose.foundation", na
 androidx-foundation-android = { group = "androidx.compose.foundation", name = "foundation-android", version.ref = "foundationAndroid" }
 richeditor-compose = { module = "com.mohamedrejeb.richeditor:richeditor-compose", version.ref = "richeditorCompose" }
 androidx-hilt-work = { group = "androidx.hilt", name = "hilt-work", version.ref = "hiltWork" }
+firebase-bom = { module = "com.google.firebase:firebase-bom", version.ref = "firebaseBom" }
+firebase-config-ktx = { module = "com.google.firebase:firebase-config-ktx" }
+firebase-analytics-ktx = { module = "com.google.firebase:firebase-analytics-ktx" }
+firebase-crashlytics-ktx = { module = "com.google.firebase:firebase-crashlytics-ktx", version.ref = "crashlytics" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }
 kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
 ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }
 hilt-android = { id = "com.google.dagger.hilt.android", version.ref = "hilt" }
-compose-compiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
\ No newline at end of file
+compose-compiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
+google-services = { id = "com.google.gms.google-services", version.ref = "googleServices" }
+firebase-crashlytics = { id = "com.google.firebase.crashlytics", version.ref = "crashlyticsPlugin" }
\ No newline at end of file