diff --git a/README.md b/README.md
index a1c8ab72..c7b904b3 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,7 @@
 # MVI-Coroutines-Flow
+## MVI-Coroutines-Flow-Clean-Architecture
+## MVI-Coroutines-Flow-Clean-Architecture-ArrowKt
+## MVI-Coroutines-Flow-Clean-Architecture-ArrowKt-KoinDI
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
 [![All Contributors](https://img.shields.io/badge/all_contributors-1-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
@@ -9,7 +12,7 @@
 [![Qodana](https://github.com/Kotlin-Android-Open-Source/MVI-Coroutines-Flow/actions/workflows/qodana.yml/badge.svg)](https://github.com/Kotlin-Android-Open-Source/MVI-Coroutines-Flow/actions/workflows/qodana.yml)
 [![Validate Gradle Wrapper](https://github.com/Kotlin-Android-Open-Source/MVI-Coroutines-Flow/actions/workflows/gradle-wrapper-validation.yml/badge.svg)](https://github.com/Kotlin-Android-Open-Source/MVI-Coroutines-Flow/actions/workflows/gradle-wrapper-validation.yml)
 [![API](https://img.shields.io/badge/API-21%2B-brightgreen.svg?style=flat)](https://android-arsenal.com/api?level=21)
-[![Kotlin](https://img.shields.io/badge/kotlin-1.7.20-blue.svg?logo=kotlin)](http://kotlinlang.org)
+[![Kotlin](https://img.shields.io/badge/kotlin-1.8.10-blue.svg?logo=kotlin)](http://kotlinlang.org)
 [![Hits](https://hits.seeyoufarm.com/api/count/incr/badge.svg?url=https%3A%2F%2Fgithub.com%2FKotlin-Android-Open-Source%2FMVI-Coroutines-Flow&count_bg=%2379C83D&title_bg=%23555555&icon=&icon_color=%23E7E7E7&title=hits&edge_flat=false)](https://hits.seeyoufarm.com)
 [![License: MIT](https://img.shields.io/badge/License-MIT-purple.svg)](https://opensource.org/licenses/MIT)
 [![Gitter](https://badges.gitter.im/Kotlin-Android-Open-Source/community.svg)](https://gitter.im/Kotlin-Android-Open-Source/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
diff --git a/build.gradle.kts b/build.gradle.kts
index 6a701040..9074980f 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -17,7 +17,7 @@ buildscript {
     classpath("com.android.tools.build:gradle:7.4.1")
     classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion")
     classpath("com.diffplug.spotless:spotless-plugin-gradle:6.15.0")
-    classpath("dev.ahmedmourad.nocopy:nocopy-gradle-plugin:1.4.0")
+    classpath("dev.drewhamilton.poko:poko-gradle-plugin:0.11.0")
     classpath("org.jacoco:org.jacoco.core:0.8.8")
     classpath("com.vanniktech:gradle-android-junit-jacoco-plugin:0.17.0-SNAPSHOT")
     classpath("com.github.ben-manes:gradle-versions-plugin:0.45.0")
diff --git a/buildSrc/src/main/kotlin/deps.kt b/buildSrc/src/main/kotlin/deps.kt
index 4f9ab5bd..22418caf 100644
--- a/buildSrc/src/main/kotlin/deps.kt
+++ b/buildSrc/src/main/kotlin/deps.kt
@@ -7,16 +7,16 @@ import org.gradle.plugin.use.PluginDependenciesSpec
 import org.gradle.plugin.use.PluginDependencySpec
 
 const val ktlintVersion = "0.46.1"
-const val kotlinVersion = "1.7.20"
+const val kotlinVersion = "1.8.10"
 
 object appConfig {
   const val applicationId = "com.hoc.flowmvi"
 
-  const val compileSdkVersion = 32
-  const val buildToolsVersion = "32.0.0"
+  const val compileSdkVersion = 33
+  const val buildToolsVersion = "33.0.1"
 
   const val minSdkVersion = 21
-  const val targetSdkVersion = 32
+  const val targetSdkVersion = 33
 
   private const val MAJOR = 2
   private const val MINOR = 1
@@ -28,16 +28,16 @@ object appConfig {
 object deps {
   object androidx {
     const val appCompat = "androidx.appcompat:appcompat:1.4.2"
-    const val coreKtx = "androidx.core:core-ktx:1.8.0"
+    const val coreKtx = "androidx.core:core-ktx:1.9.0"
     const val constraintLayout = "androidx.constraintlayout:constraintlayout:2.1.4"
     const val recyclerView = "androidx.recyclerview:recyclerview:1.2.1"
     const val swipeRefreshLayout = "androidx.swiperefreshlayout:swiperefreshlayout:1.2.0-alpha01"
-    const val material = "com.google.android.material:material:1.6.1"
+    const val material = "com.google.android.material:material:1.8.0"
     const val startup = "androidx.startup:startup-runtime:1.1.1"
   }
 
   object lifecycle {
-    private const val version = "2.5.0"
+    private const val version = "2.5.1"
 
     const val viewModelKtx = "androidx.lifecycle:lifecycle-viewmodel-ktx:$version" // viewModelScope
     const val runtimeKtx = "androidx.lifecycle:lifecycle-runtime-ktx:$version" // lifecycleScope
@@ -49,7 +49,7 @@ object deps {
     const val converterMoshi = "com.squareup.retrofit2:converter-moshi:2.9.0"
     const val loggingInterceptor = "com.squareup.okhttp3:logging-interceptor:5.0.0-alpha.10"
     const val moshiKotlin = "com.squareup.moshi:moshi-kotlin:1.13.0"
-    const val leakCanary = "com.squareup.leakcanary:leakcanary-android:2.9.1"
+    const val leakCanary = "com.squareup.leakcanary:leakcanary-android:2.10"
   }
 
   object coroutines {
@@ -61,7 +61,7 @@ object deps {
   }
 
   object koin {
-    private const val version = "3.2.0"
+    private const val version = "3.3.3"
 
     const val core = "io.insert-koin:koin-core:$version"
     const val android = "io.insert-koin:koin-android:$version"
@@ -75,7 +75,7 @@ object deps {
   const val timber = "com.jakewharton.timber:timber:5.0.1"
 
   object arrow {
-    private const val version = "1.1.3"
+    private const val version = "1.1.6-alpha.28"
     const val core = "io.arrow-kt:arrow-core:$version"
   }
 
@@ -91,7 +91,7 @@ object deps {
       }
     }
 
-    const val mockk = "io.mockk:mockk:1.12.4"
+    const val mockk = "io.mockk:mockk:1.13.4"
     const val kotlinJUnit = "org.jetbrains.kotlin:kotlin-test-junit:$kotlinVersion"
   }
 }
@@ -105,7 +105,7 @@ inline val PDsS.kotlinAndroid: PDS get() = id("kotlin-android")
 inline val PDsS.kotlin: PDS get() = id("kotlin")
 inline val PDsS.kotlinKapt: PDS get() = id("kotlin-kapt")
 inline val PDsS.kotlinParcelize: PDS get() = id("kotlin-parcelize")
-inline val PDsS.nocopyPlugin: PDS get() = id("dev.ahmedmourad.nocopy.nocopy-gradle-plugin")
+inline val PDsS.pokoPlugin: PDS get() = id("dev.drewhamilton.poko")
 
 inline val DependencyHandler.domain get() = project(":domain")
 inline val DependencyHandler.core get() = project(":core")
diff --git a/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt b/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt
new file mode 100644
index 00000000..29c7a099
--- /dev/null
+++ b/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt
@@ -0,0 +1,56 @@
+package com.hoc.flowmvi.core
+
+import arrow.core.Either
+import arrow.core.left
+import arrow.core.right
+import com.hoc.flowmvi.core.NonEmptySet.Companion.toNonEmptySetOrNull
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+/**
+ * A typealias for [Either] with [NonEmptySet] as the left side.
+ */
+typealias EitherNes<E, A> = Either<NonEmptySet<E>, A>
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun <A> A.rightNes(): EitherNes<Nothing, A> = this.right()
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun <E> E.leftNes(): EitherNes<E, Nothing> =
+  NonEmptySet.of(this).left()
+
+@OptIn(ExperimentalContracts::class)
+inline fun <E, A, B, C, Z> Either.Companion.zipOrAccumulateNonEmptySet(
+  a: EitherNes<E, A>,
+  b: EitherNes<E, B>,
+  c: EitherNes<E, C>,
+  transform: (A, B, C) -> Z,
+): EitherNes<E, Z> {
+  contract { callsInPlace(transform, InvocationKind.AT_MOST_ONCE) }
+
+  return if (
+    a is Either.Right &&
+    b is Either.Right &&
+    c is Either.Right
+  ) {
+    Either.Right(
+      transform(
+        a.value,
+        b.value,
+        c.value,
+      )
+    )
+  } else {
+    Either.Left(
+      buildSet(capacity = a.count + b.count + c.count) {
+        if (a is Either.Left) this.addAll(a.value)
+        if (b is Either.Left) this.addAll(b.value)
+        if (c is Either.Left) this.addAll(c.value)
+      }.toNonEmptySetOrNull()!!
+    )
+  }
+}
+
+@PublishedApi
+internal inline val <L, R> Either<L, R>.count: Int get() = if (isRight()) 1 else 0
diff --git a/core/src/main/java/com/hoc/flowmvi/core/ValidatedNes.kt b/core/src/main/java/com/hoc/flowmvi/core/ValidatedNes.kt
deleted file mode 100644
index 9ebb52cd..00000000
--- a/core/src/main/java/com/hoc/flowmvi/core/ValidatedNes.kt
+++ /dev/null
@@ -1,22 +0,0 @@
-package com.hoc.flowmvi.core
-
-import arrow.core.Validated
-import arrow.typeclasses.Semigroup
-
-typealias ValidatedNes<E, A> = Validated<NonEmptySet<E>, A>
-
-@Suppress("NOTHING_TO_INLINE")
-inline fun <A> A.validNes(): ValidatedNes<Nothing, A> =
-  Validated.Valid(this)
-
-@Suppress("NOTHING_TO_INLINE")
-inline fun <E> E.invalidNes(): ValidatedNes<E, Nothing> =
-  Validated.Invalid(NonEmptySet.of(this))
-
-object NonEmptySetSemigroup : Semigroup<NonEmptySet<Any?>> {
-  override fun NonEmptySet<Any?>.combine(b: NonEmptySet<Any?>): NonEmptySet<Any?> = this + b
-}
-
-@Suppress("UNCHECKED_CAST")
-fun <T> Semigroup.Companion.nonEmptySet(): Semigroup<NonEmptySet<T>> =
-  NonEmptySetSemigroup as Semigroup<NonEmptySet<T>>
diff --git a/data/src/main/java/com/hoc/flowmvi/data/UserRepositoryImpl.kt b/data/src/main/java/com/hoc/flowmvi/data/UserRepositoryImpl.kt
index 1d3cc73a..dbee5bcf 100644
--- a/data/src/main/java/com/hoc/flowmvi/data/UserRepositoryImpl.kt
+++ b/data/src/main/java/com/hoc/flowmvi/data/UserRepositoryImpl.kt
@@ -1,13 +1,13 @@
 package com.hoc.flowmvi.data
 
 import arrow.core.Either.Companion.catch as catchEither
-import arrow.core.continuations.either
+import arrow.core.getOrElse
 import arrow.core.left
 import arrow.core.leftWiden
+import arrow.core.raise.either
 import arrow.core.right
-import arrow.core.valueOr
+import com.hoc.flowmvi.core.EitherNes
 import com.hoc.flowmvi.core.Mapper
-import com.hoc.flowmvi.core.ValidatedNes
 import com.hoc.flowmvi.core.dispatchers.AppCoroutineDispatchers
 import com.hoc.flowmvi.data.remote.UserApiService
 import com.hoc.flowmvi.data.remote.UserBody
@@ -16,6 +16,7 @@ import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.model.UserError
 import com.hoc.flowmvi.domain.model.UserValidationError
 import com.hoc.flowmvi.domain.repository.UserRepository
+import com.hoc081098.flowext.flowFromSuspend
 import com.hoc081098.flowext.retryWithExponentialBackoff
 import java.io.IOException
 import kotlin.time.Duration.Companion.milliseconds
@@ -24,7 +25,6 @@ import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
-import kotlinx.coroutines.flow.asFlow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flatMapConcat
@@ -40,7 +40,7 @@ import timber.log.Timber
 internal class UserRepositoryImpl(
   private val userApiService: UserApiService,
   private val dispatchers: AppCoroutineDispatchers,
-  private val responseToDomain: Mapper<UserResponse, ValidatedNes<UserValidationError, User>>,
+  private val responseToDomain: Mapper<UserResponse, EitherNes<UserValidationError, User>>,
   private val domainToBody: Mapper<User, UserBody>,
   private val errorMapper: Mapper<Throwable, UserError>,
 ) : UserRepository {
@@ -51,29 +51,21 @@ internal class UserRepositoryImpl(
     class Added(val user: User) : Change()
   }
 
-  private val responseToDomainThrows: (UserResponse) -> User = { response ->
-    responseToDomain(response).let { validated ->
-      validated.valueOr {
-        val t = UserError.ValidationFailed(it.toSet())
-        logError(t, "Map $response to user")
-        throw t
-      }
-    }
-  }
-
   private val changesFlow = MutableSharedFlow<Change>(extraBufferCapacity = 64)
-
   private suspend inline fun sendChange(change: Change) = changesFlow.emit(change)
 
-  @Suppress("NOTHING_TO_INLINE")
-  private inline fun logError(t: Throwable, message: String) = Timber.tag(TAG).e(t, message)
-
-  private fun getUsersFromRemote(): Flow<List<User>> = suspend {
+  private fun getUsersFromRemote(): Flow<List<User>> = flowFromSuspend {
     Timber.d("[USER_REPO] getUsersFromRemote ...")
+
     userApiService
       .getUsers()
-      .map(responseToDomainThrows)
-  }.asFlow()
+      .map { response ->
+        responseToDomain(response)
+          .mapLeft(UserError::ValidationFailed)
+          .onLeft { logError(it, "Map $response to user") }
+          .getOrElse { throw it }
+      }
+  }
     .retryWithExponentialBackoff(
       maxAttempt = 2,
       initialDelay = 500.milliseconds,
@@ -100,50 +92,65 @@ internal class UserRepositoryImpl(
     }
 
   override suspend fun refresh() = catchEither { getUsersFromRemote().first() }
-    .tap { sendChange(Change.Refreshed(it)) }
+    .onRight { sendChange(Change.Refreshed(it)) }
     .map { }
-    .tapLeft { logError(it, "refresh") }
+    .onLeft { logError(it, "refresh") }
     .mapLeft(errorMapper)
 
-  override suspend fun remove(user: User) = either<UserError, Unit> {
+  override suspend fun remove(user: User) = either {
     withContext(dispatchers.io) {
       val response = catchEither { userApiService.remove(user.id) }
-        .tapLeft { logError(it, "remove user=$user") }
+        .onLeft { logError(it, "remove user=$user") }
         .mapLeft(errorMapper)
         .bind()
 
       val deleted = responseToDomain(response)
-        .mapLeft { UserError.ValidationFailed(it.toSet()) }
-        .tapInvalid { logError(it, "remove user=$user") }
+        .mapLeft { UserError.ValidationFailed(it) }
+        .onLeft { logError(it, "remove user=$user") }
         .bind()
 
       sendChange(Change.Removed(deleted))
     }
   }
 
-  override suspend fun add(user: User) = either<UserError, Unit> {
+  override suspend fun add(user: User) = either {
     withContext(dispatchers.io) {
       val response = catchEither { userApiService.add(domainToBody(user)) }
-        .tapLeft { logError(it, "add user=$user") }
+        .onLeft { logError(it, "add user=$user") }
         .mapLeft(errorMapper)
         .bind()
 
       val added = responseToDomain(response)
-        .mapLeft { UserError.ValidationFailed(it.toSet()) }
-        .tapInvalid { logError(it, "add user=$user") }
+        .mapLeft { UserError.ValidationFailed(it) }
+        .onLeft { logError(it, "add user=$user") }
         .bind()
 
       sendChange(Change.Added(added))
     }
   }
 
-  override suspend fun search(query: String) = withContext(dispatchers.io) {
-    catchEither { userApiService.search(query).map(responseToDomainThrows) }
-      .tapLeft { logError(it, "search query=$query") }
-      .mapLeft(errorMapper)
+  override suspend fun search(query: String) = either {
+    withContext(dispatchers.io) {
+      val userResponses = catchEither { userApiService.search(query) }
+        .onLeft { logError(it, "search query=$query") }
+        .mapLeft(errorMapper)
+        .bind()
+
+      val users = userResponses.map { userResponse ->
+        responseToDomain(userResponse)
+          .mapLeft(UserError::ValidationFailed)
+          .onLeft { logError(it, "search query=$query") }
+          .bind()
+      }
+
+      users
+    }
   }
 
   private companion object {
+    @Suppress("NOTHING_TO_INLINE")
+    private inline fun logError(t: Throwable, message: String) = Timber.tag(TAG).e(t, message)
+
     private val TAG = UserRepositoryImpl::class.java.simpleName
   }
 }
diff --git a/data/src/main/java/com/hoc/flowmvi/data/mapper/UserErrorMapper.kt b/data/src/main/java/com/hoc/flowmvi/data/mapper/UserErrorMapper.kt
index 71d36900..ef48d351 100644
--- a/data/src/main/java/com/hoc/flowmvi/data/mapper/UserErrorMapper.kt
+++ b/data/src/main/java/com/hoc/flowmvi/data/mapper/UserErrorMapper.kt
@@ -4,6 +4,7 @@ import arrow.core.nonFatalOrThrow
 import com.hoc.flowmvi.core.Mapper
 import com.hoc.flowmvi.data.remote.ErrorResponse
 import com.hoc.flowmvi.domain.model.UserError
+import com.hoc.flowmvi.domain.model.UserValidationError
 import com.squareup.moshi.JsonAdapter
 import java.io.IOException
 import java.net.SocketException
@@ -48,7 +49,9 @@ internal class UserErrorMapper(private val errorResponseJsonAdapter: JsonAdapter
       "internal-error" -> UserError.ServerError
       "invalid-id" -> UserError.InvalidId(id = errorResponse.data as String)
       "user-not-found" -> UserError.UserNotFound(id = errorResponse.data as String)
-      "validation-failed" -> UserError.ValidationFailed(errors = emptySet())
+      "validation-failed" -> UserError.ValidationFailed(
+        errors = UserValidationError.VALUES_SET // TODO(hoc081098): Map validation errors from server response
+      )
       else -> UserError.Unexpected
     }
   }
diff --git a/data/src/main/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapper.kt b/data/src/main/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapper.kt
index 4d6de239..0201a373 100644
--- a/data/src/main/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapper.kt
+++ b/data/src/main/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapper.kt
@@ -1,14 +1,14 @@
 package com.hoc.flowmvi.data.mapper
 
+import com.hoc.flowmvi.core.EitherNes
 import com.hoc.flowmvi.core.Mapper
-import com.hoc.flowmvi.core.ValidatedNes
 import com.hoc.flowmvi.data.remote.UserResponse
 import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.model.UserValidationError
 
 internal class UserResponseToUserDomainMapper :
-  Mapper<UserResponse, ValidatedNes<UserValidationError, User>> {
-  override fun invoke(response: UserResponse): ValidatedNes<UserValidationError, User> {
+  Mapper<UserResponse, EitherNes<UserValidationError, User>> {
+  override fun invoke(response: UserResponse): EitherNes<UserValidationError, User> {
     return User.create(
       id = response.id,
       avatar = response.avatar,
diff --git a/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplRealAPITest.kt b/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplRealAPITest.kt
index ebdc606f..9516cc59 100644
--- a/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplRealAPITest.kt
+++ b/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplRealAPITest.kt
@@ -3,7 +3,7 @@ package com.hoc.flowmvi.data
 import android.util.Log
 import com.hoc.flowmvi.core.dispatchers.AppCoroutineDispatchers
 import com.hoc.flowmvi.domain.repository.UserRepository
-import com.hoc.flowmvi.test_utils.getOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import java.time.LocalDateTime
 import java.time.format.DateTimeFormatter
 import kotlin.test.Test
@@ -61,7 +61,7 @@ class UserRepositoryImplRealAPITest : KoinTest {
         .getUsers()
         .first()
       assertTrue(result.isRight())
-      assertTrue(result.getOrThrow.isNotEmpty())
+      assertTrue(result.rightValueOrThrow.isNotEmpty())
     }
     Unit
   }
diff --git a/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplTest.kt b/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplTest.kt
index 153cb64c..cccb7004 100644
--- a/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplTest.kt
+++ b/data/src/test/java/com/hoc/flowmvi/data/UserRepositoryImplTest.kt
@@ -1,9 +1,9 @@
 package com.hoc.flowmvi.data
 
 import arrow.core.Either
+import com.hoc.flowmvi.core.EitherNes
 import com.hoc.flowmvi.core.Mapper
-import com.hoc.flowmvi.core.ValidatedNes
-import com.hoc.flowmvi.core.validNes
+import com.hoc.flowmvi.core.rightNes
 import com.hoc.flowmvi.data.remote.UserApiService
 import com.hoc.flowmvi.data.remote.UserBody
 import com.hoc.flowmvi.data.remote.UserResponse
@@ -12,9 +12,8 @@ import com.hoc.flowmvi.domain.model.UserError
 import com.hoc.flowmvi.domain.model.UserValidationError
 import com.hoc.flowmvi.test_utils.TestAppCoroutineDispatchers
 import com.hoc.flowmvi.test_utils.TestCoroutineDispatcherRule
-import com.hoc.flowmvi.test_utils.getOrThrow
-import com.hoc.flowmvi.test_utils.leftOrThrow
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.leftValueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import io.mockk.clearAllMocks
 import io.mockk.coEvery
 import io.mockk.coVerify
@@ -95,9 +94,9 @@ private val USERS = listOf(
     lastName = "last",
     avatar = "avatar3",
   ),
-).map { it.valueOrThrow }
+).map { it.rightValueOrThrow }
 
-private val VALID_NES_USERS = USERS.map(User::validNes)
+private val VALID_NES_USERS = USERS.map(User::rightNes)
 
 @FlowPreview
 @ExperimentalCoroutinesApi
@@ -108,7 +107,7 @@ class UserRepositoryImplTest {
 
   private lateinit var repo: UserRepositoryImpl
   private lateinit var userApiService: UserApiService
-  private lateinit var responseToDomain: Mapper<UserResponse, ValidatedNes<UserValidationError, User>>
+  private lateinit var responseToDomain: Mapper<UserResponse, EitherNes<UserValidationError, User>>
   private lateinit var domainToBody: Mapper<User, UserBody>
   private lateinit var errorMapper: Mapper<Throwable, UserError>
 
@@ -147,7 +146,7 @@ class UserRepositoryImplTest {
     val result = repo.refresh()
 
     assertTrue(result.isRight())
-    assertNotNull(result.orNull())
+    assertNotNull(result.getOrNull())
 
     coVerify { userApiService.getUsers() }
     verifySequence {
@@ -166,7 +165,7 @@ class UserRepositoryImplTest {
     val result = repo.refresh()
 
     assertTrue(result.isLeft())
-    assertEquals(UserError.NetworkError, result.leftOrThrow)
+    assertEquals(UserError.NetworkError, result.leftValueOrThrow)
     coVerify(exactly = 3) { userApiService.getUsers() } // retry 2 times
     verify(exactly = 1) { errorMapper(ofType<IOException>()) }
   }
@@ -177,12 +176,12 @@ class UserRepositoryImplTest {
     val userResponse = USER_RESPONSES[0]
 
     coEvery { userApiService.remove(user.id) } returns userResponse
-    every { responseToDomain(userResponse) } returns user.validNes()
+    every { responseToDomain(userResponse) } returns user.rightNes()
 
     val result = repo.remove(user)
 
     assertTrue(result.isRight())
-    assertNotNull(result.orNull())
+    assertNotNull(result.getOrNull())
 
     coVerify { userApiService.remove(user.id) }
     coVerify { responseToDomain(userResponse) }
@@ -197,7 +196,7 @@ class UserRepositoryImplTest {
     val result = repo.remove(user)
 
     assertTrue(result.isLeft())
-    assertEquals(UserError.NetworkError, result.leftOrThrow)
+    assertEquals(UserError.NetworkError, result.leftValueOrThrow)
     coVerify(exactly = 1) { userApiService.remove(user.id) }
     verify(exactly = 1) { errorMapper(ofType<IOException>()) }
   }
@@ -209,12 +208,12 @@ class UserRepositoryImplTest {
 
     coEvery { userApiService.add(USER_BODY) } returns userResponse
     every { domainToBody(user) } returns USER_BODY
-    every { responseToDomain(userResponse) } returns user.validNes()
+    every { responseToDomain(userResponse) } returns user.rightNes()
 
     val result = repo.add(user)
 
     assertTrue(result.isRight())
-    assertNotNull(result.orNull())
+    assertNotNull(result.getOrNull())
 
     coVerify { userApiService.add(USER_BODY) }
     verify { domainToBody(user) }
@@ -231,7 +230,7 @@ class UserRepositoryImplTest {
     val result = repo.add(user)
 
     assertTrue(result.isLeft())
-    assertEquals(UserError.NetworkError, result.leftOrThrow)
+    assertEquals(UserError.NetworkError, result.leftValueOrThrow)
 
     coVerify(exactly = 1) { userApiService.add(USER_BODY) }
     verify(exactly = 1) { domainToBody(user) }
@@ -247,8 +246,8 @@ class UserRepositoryImplTest {
     val result = repo.search(q)
 
     assertTrue(result.isRight())
-    assertNotNull(result.orNull())
-    assertContentEquals(USERS, result.getOrThrow)
+    assertNotNull(result.getOrNull())
+    assertContentEquals(USERS, result.rightValueOrThrow)
 
     coVerify { userApiService.search(q) }
     coVerifySequence {
@@ -267,7 +266,7 @@ class UserRepositoryImplTest {
     val result = repo.search(q)
 
     assertTrue(result.isLeft())
-    assertEquals(UserError.NetworkError, result.leftOrThrow)
+    assertEquals(UserError.NetworkError, result.leftValueOrThrow)
 
     coVerify(exactly = 1) { userApiService.search(q) }
     verify(exactly = 1) { errorMapper(ofType<IOException>()) }
@@ -288,8 +287,8 @@ class UserRepositoryImplTest {
     assertEquals(1, events.size)
     val result = events.single()
     assertTrue(result.isRight())
-    assertNotNull(result.orNull())
-    assertEquals(USERS, result.getOrThrow)
+    assertNotNull(result.getOrNull())
+    assertEquals(USERS, result.rightValueOrThrow)
 
     coVerify { userApiService.getUsers() }
     verifySequence {
@@ -314,8 +313,8 @@ class UserRepositoryImplTest {
     assertEquals(1, events.size)
     val result = events.single()
     assertTrue(result.isLeft())
-    assertNull(result.orNull())
-    assertEquals(UserError.NetworkError, result.leftOrThrow)
+    assertNull(result.getOrNull())
+    assertEquals(UserError.NetworkError, result.leftValueOrThrow)
 
     coVerify(exactly = 3) { userApiService.getUsers() } // retry 2 times.
     verify(exactly = 1) { errorMapper(ofType<IOException>()) }
@@ -331,7 +330,7 @@ class UserRepositoryImplTest {
       coEvery { userApiService.remove(user.id) } returns userResponse
       every { domainToBody(user) } returns USER_BODY
       USER_RESPONSES.zip(USERS)
-        .forEach { (r, u) -> every { responseToDomain(r) } returns u.validNes() }
+        .forEach { (r, u) -> every { responseToDomain(r) } returns u.rightNes() }
 
       val events = mutableListOf<Either<UserError, List<User>>>()
       val job = launch(start = CoroutineStart.UNDISPATCHED) {
@@ -343,7 +342,7 @@ class UserRepositoryImplTest {
       job.cancel()
 
       assertContentEquals(
-        events.map { it.getOrThrow },
+        events.map { it.rightValueOrThrow },
         listOf(
           USERS.dropLast(1),
           USERS,
diff --git a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserDomainToUserBodyMapperTest.kt b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserDomainToUserBodyMapperTest.kt
index c0c9a20c..56586c13 100644
--- a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserDomainToUserBodyMapperTest.kt
+++ b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserDomainToUserBodyMapperTest.kt
@@ -2,7 +2,7 @@ package com.hoc.flowmvi.data.mapper
 
 import com.hoc.flowmvi.data.remote.UserBody
 import com.hoc.flowmvi.domain.model.User
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -18,7 +18,7 @@ class UserDomainToUserBodyMapperTest {
         firstName = "first",
         lastName = "last",
         avatar = "avatar",
-      ).valueOrThrow
+      ).rightValueOrThrow
     )
 
     assertEquals(
diff --git a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserErrorMapperTest.kt b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserErrorMapperTest.kt
index 9daeac95..301fec7b 100644
--- a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserErrorMapperTest.kt
+++ b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserErrorMapperTest.kt
@@ -1,7 +1,9 @@
 package com.hoc.flowmvi.data.mapper
 
+import com.hoc.flowmvi.core.NonEmptySet
 import com.hoc.flowmvi.data.remote.ErrorResponse
 import com.hoc.flowmvi.domain.model.UserError
+import com.hoc.flowmvi.domain.model.UserValidationError
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.adapter
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
@@ -49,8 +51,8 @@ class UserErrorMapperTest {
     assertEquals(UserError.UserNotFound("1"), errorMapper(UserError.UserNotFound("1")))
     assertEquals(UserError.InvalidId("1"), errorMapper(UserError.InvalidId("1")))
     assertEquals(
-      UserError.ValidationFailed(emptySet()),
-      errorMapper(UserError.ValidationFailed(emptySet())),
+      UserError.ValidationFailed(NonEmptySet.of(UserValidationError.INVALID_EMAIL_ADDRESS)),
+      errorMapper(UserError.ValidationFailed(NonEmptySet.of(UserValidationError.INVALID_EMAIL_ADDRESS))),
     )
     assertEquals(UserError.ServerError, errorMapper(UserError.ServerError))
     assertEquals(UserError.Unexpected, errorMapper(UserError.Unexpected))
@@ -158,7 +160,7 @@ class UserErrorMapperTest {
       errorMapper(buildHttpException("user-not-found", id)),
     )
     assertEquals(
-      UserError.ValidationFailed(emptySet()),
+      UserError.ValidationFailed(UserValidationError.VALUES_SET),
       errorMapper(buildHttpException("validation-failed", null)),
     )
   }
diff --git a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapperTest.kt b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapperTest.kt
index 628a89a5..73f868fd 100644
--- a/data/src/test/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapperTest.kt
+++ b/data/src/test/java/com/hoc/flowmvi/data/mapper/UserResponseToUserDomainMapperTest.kt
@@ -3,8 +3,8 @@ package com.hoc.flowmvi.data.mapper
 import com.hoc.flowmvi.data.remote.UserResponse
 import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.model.UserValidationError
-import com.hoc.flowmvi.test_utils.invalidValueOrThrow
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.leftValueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
@@ -23,7 +23,7 @@ class UserResponseToUserDomainMapperTest {
         avatar = "avatar",
       )
     )
-    assertTrue(validated.isValid)
+    assertTrue(validated.isRight())
     assertEquals(
       User.create(
         id = "id",
@@ -31,8 +31,8 @@ class UserResponseToUserDomainMapperTest {
         firstName = "first",
         lastName = "last",
         avatar = "avatar",
-      ).valueOrThrow,
-      validated.valueOrThrow,
+      ).rightValueOrThrow,
+      validated.rightValueOrThrow,
     )
   }
 
@@ -47,10 +47,10 @@ class UserResponseToUserDomainMapperTest {
         avatar = "avatar",
       )
     )
-    assertTrue(validated.isInvalid)
+    assertTrue(validated.isLeft())
     assertEquals(
       UserValidationError.INVALID_EMAIL_ADDRESS,
-      validated.invalidValueOrThrow.single(),
+      validated.leftValueOrThrow.single(),
     )
   }
 }
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/Email.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/Email.kt
index c0276bb9..3100750d 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/Email.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/Email.kt
@@ -1,11 +1,11 @@
 package com.hoc.flowmvi.domain.model
 
-import com.hoc.flowmvi.core.ValidatedNes
+import com.hoc.flowmvi.core.EitherNes
 
 @JvmInline
 value class Email private constructor(val value: String) {
   companion object {
-    fun create(value: String?): ValidatedNes<UserValidationError, Email> =
+    fun create(value: String?): EitherNes<UserValidationError, Email> =
       validateEmail(value).map(::Email)
   }
 }
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/FirstName.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/FirstName.kt
index 0c54f5f8..13368849 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/FirstName.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/FirstName.kt
@@ -1,11 +1,11 @@
 package com.hoc.flowmvi.domain.model
 
-import com.hoc.flowmvi.core.ValidatedNes
+import com.hoc.flowmvi.core.EitherNes
 
 @JvmInline
 value class FirstName private constructor(val value: String) {
   companion object {
-    fun create(value: String?): ValidatedNes<UserValidationError, FirstName> =
+    fun create(value: String?): EitherNes<UserValidationError, FirstName> =
       validateFirstName(value).map(::FirstName)
   }
 }
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/LastName.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/LastName.kt
index 59f62b20..b88224da 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/LastName.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/LastName.kt
@@ -1,11 +1,11 @@
 package com.hoc.flowmvi.domain.model
 
-import com.hoc.flowmvi.core.ValidatedNes
+import com.hoc.flowmvi.core.EitherNes
 
 @JvmInline
 value class LastName private constructor(val value: String) {
   companion object {
-    fun create(value: String?): ValidatedNes<UserValidationError, LastName> =
+    fun create(value: String?): EitherNes<UserValidationError, LastName> =
       validateLastName(value).map(::LastName)
   }
 }
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/User.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/User.kt
index bca26ec3..7a067970 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/User.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/User.kt
@@ -1,10 +1,9 @@
 package com.hoc.flowmvi.domain.model
 
-import arrow.core.zip
-import arrow.typeclasses.Semigroup
-import com.hoc.flowmvi.core.ValidatedNes
-import com.hoc.flowmvi.core.nonEmptySet
-import com.hoc.flowmvi.core.validNes
+import arrow.core.Either
+import com.hoc.flowmvi.core.EitherNes
+import com.hoc.flowmvi.core.rightNes
+import com.hoc.flowmvi.core.zipOrAccumulateNonEmptySet
 
 data class User(
   val id: String,
@@ -20,45 +19,44 @@ data class User(
       firstName: String?,
       lastName: String?,
       avatar: String,
-    ): ValidatedNes<UserValidationError, User> = Email.create(email)
-      .zip(
-        Semigroup.nonEmptySet(),
-        FirstName.create(firstName),
-        LastName.create(lastName),
-      ) { e, f, l ->
-        User(
-          firstName = f,
-          email = e,
-          lastName = l,
-          id = id,
-          avatar = avatar
-        )
-      }
+    ): EitherNes<UserValidationError, User> = Either.zipOrAccumulateNonEmptySet(
+      Email.create(email),
+      FirstName.create(firstName),
+      LastName.create(lastName)
+    ) { e, f, l ->
+      User(
+        firstName = f,
+        email = e,
+        lastName = l,
+        id = id,
+        avatar = avatar
+      )
+    }
   }
 }
 
-internal fun validateFirstName(firstName: String?): ValidatedNes<UserValidationError, String> {
+internal fun validateFirstName(firstName: String?): EitherNes<UserValidationError, String> {
   if (firstName == null || firstName.length < MIN_LENGTH_FIRST_NAME) {
-    return UserValidationError.TOO_SHORT_FIRST_NAME.asInvalidNes
+    return UserValidationError.TOO_SHORT_FIRST_NAME.asLeftNes
   }
   // more validations here
-  return firstName.validNes()
+  return firstName.rightNes()
 }
 
-internal fun validateLastName(lastName: String?): ValidatedNes<UserValidationError, String> {
+internal fun validateLastName(lastName: String?): EitherNes<UserValidationError, String> {
   if (lastName == null || lastName.length < MIN_LENGTH_LAST_NAME) {
-    return UserValidationError.TOO_SHORT_LAST_NAME.asInvalidNes
+    return UserValidationError.TOO_SHORT_LAST_NAME.asLeftNes
   }
   // more validations here
-  return lastName.validNes()
+  return lastName.rightNes()
 }
 
-internal fun validateEmail(email: String?): ValidatedNes<UserValidationError, String> {
+internal fun validateEmail(email: String?): EitherNes<UserValidationError, String> {
   if (email == null || !EMAIL_ADDRESS_REGEX.matches(email)) {
-    return UserValidationError.INVALID_EMAIL_ADDRESS.asInvalidNes
+    return UserValidationError.INVALID_EMAIL_ADDRESS.asLeftNes
   }
   // more validations here
-  return email.validNes()
+  return email.rightNes()
 }
 
 private const val MIN_LENGTH_FIRST_NAME = 3
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/UserError.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/UserError.kt
index 33a723ec..26e1493d 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/UserError.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/UserError.kt
@@ -1,10 +1,12 @@
 package com.hoc.flowmvi.domain.model
 
+import com.hoc.flowmvi.core.NonEmptySet
+
 sealed class UserError : Throwable() {
   object NetworkError : UserError()
   data class UserNotFound(val id: String) : UserError()
   data class InvalidId(val id: String) : UserError()
-  data class ValidationFailed(val errors: Set<UserValidationError>) : UserError()
+  data class ValidationFailed(val errors: NonEmptySet<UserValidationError>) : UserError()
   object ServerError : UserError()
   object Unexpected : UserError()
 }
diff --git a/domain/src/main/java/com/hoc/flowmvi/domain/model/UserValidationError.kt b/domain/src/main/java/com/hoc/flowmvi/domain/model/UserValidationError.kt
index b71fd03b..1aedce2e 100644
--- a/domain/src/main/java/com/hoc/flowmvi/domain/model/UserValidationError.kt
+++ b/domain/src/main/java/com/hoc/flowmvi/domain/model/UserValidationError.kt
@@ -1,24 +1,26 @@
 package com.hoc.flowmvi.domain.model
 
+import com.hoc.flowmvi.core.EitherNes
 import com.hoc.flowmvi.core.NonEmptySet
 import com.hoc.flowmvi.core.NonEmptySet.Companion.toNonEmptySetOrNull
-import com.hoc.flowmvi.core.ValidatedNes
-import com.hoc.flowmvi.core.invalidNes
+import com.hoc.flowmvi.core.leftNes
 
 enum class UserValidationError {
   INVALID_EMAIL_ADDRESS,
   TOO_SHORT_FIRST_NAME,
   TOO_SHORT_LAST_NAME;
 
-  val asInvalidNes: ValidatedNes<UserValidationError, Nothing> = invalidNes()
+  val asLeftNes: EitherNes<UserValidationError, Nothing> = leftNes()
 
   companion object {
     /**
      * Use this instead of [values()] for more performant.
      * See [KT-48872](https://youtrack.jetbrains.com/issue/KT-48872)
      */
+    @JvmField
     val VALUES: List<UserValidationError> = values().asList()
 
+    @JvmField
     val VALUES_SET: NonEmptySet<UserValidationError> = VALUES.toNonEmptySetOrNull()!!
   }
 }
diff --git a/domain/src/test/java/com/hoc/flowmvi/domain/Email_FirstName_LastName_Test.kt b/domain/src/test/java/com/hoc/flowmvi/domain/Email_FirstName_LastName_Test.kt
index f0797439..24f12124 100644
--- a/domain/src/test/java/com/hoc/flowmvi/domain/Email_FirstName_LastName_Test.kt
+++ b/domain/src/test/java/com/hoc/flowmvi/domain/Email_FirstName_LastName_Test.kt
@@ -1,10 +1,10 @@
 package com.hoc.flowmvi.ui.add
 
-import arrow.core.orNull
 import com.hoc.flowmvi.domain.model.Email
 import com.hoc.flowmvi.domain.model.FirstName
 import com.hoc.flowmvi.domain.model.LastName
 import com.hoc.flowmvi.domain.model.UserValidationError
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
@@ -16,29 +16,29 @@ class Email_FirstName_LastName_Test {
   @Test
   fun testCreateEmail_withValidEmail_returnsValid() {
     val validated = Email.create("hoc081098@gmail.com")
-    assertTrue(validated.isValid)
+    assertTrue(validated.isRight())
     assertEquals(
       "hoc081098@gmail.com",
-      validated.orNull()?.value,
+      validated.rightValueOrThrow.value,
     )
   }
 
   @Test
   fun testCreateEmail_withInvalidEmail_returnsInvalid() {
     assertEquals(
-      UserValidationError.INVALID_EMAIL_ADDRESS.asInvalidNes,
+      UserValidationError.INVALID_EMAIL_ADDRESS.asLeftNes,
       Email.create(null),
     )
     assertEquals(
-      UserValidationError.INVALID_EMAIL_ADDRESS.asInvalidNes,
+      UserValidationError.INVALID_EMAIL_ADDRESS.asLeftNes,
       Email.create(""),
     )
     assertEquals(
-      UserValidationError.INVALID_EMAIL_ADDRESS.asInvalidNes,
+      UserValidationError.INVALID_EMAIL_ADDRESS.asLeftNes,
       Email.create("a"),
     )
     assertEquals(
-      UserValidationError.INVALID_EMAIL_ADDRESS.asInvalidNes,
+      UserValidationError.INVALID_EMAIL_ADDRESS.asLeftNes,
       Email.create("a@"),
     )
   }
@@ -46,29 +46,29 @@ class Email_FirstName_LastName_Test {
   @Test
   fun testCreateFirstName_withValidFirstName_returnsValid() {
     val validated = FirstName.create("hoc081098")
-    assertTrue(validated.isValid)
+    assertTrue(validated.isRight())
     assertEquals(
       "hoc081098",
-      validated.orNull()?.value,
+      validated.rightValueOrThrow.value,
     )
   }
 
   @Test
   fun testCreateFirstName_withInvalidFirstName_returnsInvalid() {
     assertEquals(
-      UserValidationError.TOO_SHORT_FIRST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_FIRST_NAME.asLeftNes,
       FirstName.create(null),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_FIRST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_FIRST_NAME.asLeftNes,
       FirstName.create(""),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_FIRST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_FIRST_NAME.asLeftNes,
       FirstName.create("a"),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_FIRST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_FIRST_NAME.asLeftNes,
       FirstName.create("ab"),
     )
   }
@@ -76,29 +76,29 @@ class Email_FirstName_LastName_Test {
   @Test
   fun testCreateLastName_withValidLastName_returnsValid() {
     val validated = LastName.create("hoc081098")
-    assertTrue(validated.isValid)
+    assertTrue(validated.isRight())
     assertEquals(
       "hoc081098",
-      validated.orNull()?.value,
+      validated.rightValueOrThrow.value,
     )
   }
 
   @Test
   fun testCreateLastName_withInvalidLastName_returnsInvalid() {
     assertEquals(
-      UserValidationError.TOO_SHORT_LAST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_LAST_NAME.asLeftNes,
       LastName.create(null),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_LAST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_LAST_NAME.asLeftNes,
       LastName.create(""),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_LAST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_LAST_NAME.asLeftNes,
       LastName.create("a"),
     )
     assertEquals(
-      UserValidationError.TOO_SHORT_LAST_NAME.asInvalidNes,
+      UserValidationError.TOO_SHORT_LAST_NAME.asLeftNes,
       LastName.create("ab"),
     )
   }
diff --git a/domain/src/test/java/com/hoc/flowmvi/domain/UseCaseTest.kt b/domain/src/test/java/com/hoc/flowmvi/domain/UseCaseTest.kt
index a0bbb45e..7b75e88d 100644
--- a/domain/src/test/java/com/hoc/flowmvi/domain/UseCaseTest.kt
+++ b/domain/src/test/java/com/hoc/flowmvi/domain/UseCaseTest.kt
@@ -11,7 +11,7 @@ import com.hoc.flowmvi.domain.usecase.RefreshGetUsersUseCase
 import com.hoc.flowmvi.domain.usecase.RemoveUserUseCase
 import com.hoc.flowmvi.domain.usecase.SearchUsersUseCase
 import com.hoc.flowmvi.test_utils.TestCoroutineDispatcherRule
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import io.mockk.clearAllMocks
 import io.mockk.coEvery
 import io.mockk.coVerify
@@ -51,7 +51,7 @@ private val USERS = listOf(
     lastName = "last3",
     avatar = "3.png"
   ),
-).map { it.valueOrThrow }
+).map { it.rightValueOrThrow }
 
 @ExperimentalCoroutinesApi
 class UseCaseTest {
diff --git a/domain/src/test/java/com/hoc/flowmvi/domain/UserTest.kt b/domain/src/test/java/com/hoc/flowmvi/domain/UserTest.kt
index 79d952e9..348ac36f 100644
--- a/domain/src/test/java/com/hoc/flowmvi/domain/UserTest.kt
+++ b/domain/src/test/java/com/hoc/flowmvi/domain/UserTest.kt
@@ -2,8 +2,8 @@ package com.hoc.flowmvi.domain
 
 import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.model.UserValidationError
-import com.hoc.flowmvi.test_utils.invalidValueOrThrow
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.leftValueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
@@ -23,8 +23,8 @@ class UserTest {
       lastName = VALID_NAME,
       avatar = AVATAR,
     )
-    assertTrue(validated.isValid)
-    validated.valueOrThrow.let { user ->
+    assertTrue(validated.isRight())
+    validated.rightValueOrThrow.let { user ->
       assertEquals(ID, user.id)
       assertEquals(VALID_EMAIL, user.email.value)
       assertEquals(VALID_NAME, user.firstName.value)
@@ -42,8 +42,8 @@ class UserTest {
       lastName = VALID_NAME,
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
-    assertEquals(UserValidationError.INVALID_EMAIL_ADDRESS, validated.invalidValueOrThrow.single())
+    assertTrue(validated.isLeft())
+    assertEquals(UserValidationError.INVALID_EMAIL_ADDRESS, validated.leftValueOrThrow.single())
   }
 
   @Test
@@ -55,8 +55,8 @@ class UserTest {
       lastName = VALID_NAME,
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
-    assertEquals(UserValidationError.TOO_SHORT_FIRST_NAME, validated.invalidValueOrThrow.single())
+    assertTrue(validated.isLeft())
+    assertEquals(UserValidationError.TOO_SHORT_FIRST_NAME, validated.leftValueOrThrow.single())
   }
 
   @Test
@@ -68,8 +68,8 @@ class UserTest {
       lastName = "h",
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
-    assertEquals(UserValidationError.TOO_SHORT_LAST_NAME, validated.invalidValueOrThrow.single())
+    assertTrue(validated.isLeft())
+    assertEquals(UserValidationError.TOO_SHORT_LAST_NAME, validated.leftValueOrThrow.single())
   }
 
   @Test
@@ -81,13 +81,13 @@ class UserTest {
       lastName = VALID_NAME,
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
+    assertTrue(validated.isLeft())
     assertEquals(
       setOf(
         UserValidationError.INVALID_EMAIL_ADDRESS,
         UserValidationError.TOO_SHORT_FIRST_NAME,
       ),
-      validated.invalidValueOrThrow.toSet()
+      validated.leftValueOrThrow.toSet()
     )
   }
 
@@ -100,13 +100,13 @@ class UserTest {
       lastName = "h",
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
+    assertTrue(validated.isLeft())
     assertEquals(
       setOf(
         UserValidationError.INVALID_EMAIL_ADDRESS,
         UserValidationError.TOO_SHORT_LAST_NAME,
       ),
-      validated.invalidValueOrThrow.toSet()
+      validated.leftValueOrThrow.toSet()
     )
   }
 
@@ -119,13 +119,13 @@ class UserTest {
       lastName = "h",
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
+    assertTrue(validated.isLeft())
     assertEquals(
       setOf(
         UserValidationError.TOO_SHORT_FIRST_NAME,
         UserValidationError.TOO_SHORT_LAST_NAME,
       ),
-      validated.invalidValueOrThrow.toSet()
+      validated.leftValueOrThrow.toSet()
     )
   }
 
@@ -138,10 +138,10 @@ class UserTest {
       lastName = "h",
       avatar = AVATAR,
     )
-    assertTrue(validated.isInvalid)
+    assertTrue(validated.isLeft())
     assertEquals(
       UserValidationError.values().toSet(),
-      validated.invalidValueOrThrow.toSet()
+      validated.leftValueOrThrow.toSet()
     )
   }
 }
diff --git a/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddContract.kt b/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddContract.kt
index 0b56a350..49ec7c0a 100644
--- a/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddContract.kt
+++ b/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddContract.kt
@@ -4,7 +4,7 @@ import android.os.Bundle
 import android.os.Parcelable
 import androidx.core.os.bundleOf
 import arrow.core.identity
-import com.hoc.flowmvi.core.ValidatedNes
+import com.hoc.flowmvi.core.EitherNes
 import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.model.UserError
 import com.hoc.flowmvi.domain.model.UserValidationError
@@ -71,15 +71,15 @@ internal sealed interface PartialStateChange {
     val email: String,
     val firstName: String,
     val lastName: String,
-    val userValidatedNes: ValidatedNes<UserValidationError, User>,
+    val userEitherNes: EitherNes<UserValidationError, User>,
   ) : PartialStateChange {
     override fun reduce(viewState: ViewState): ViewState = viewState.copy(
       email = email,
       firstName = firstName,
       lastName = lastName,
-      errors = userValidatedNes.fold(
-        fe = ::identity,
-        fa = { emptySet() },
+      errors = userEitherNes.fold(
+        ifLeft = ::identity,
+        ifRight = { emptySet() },
       ),
     )
   }
diff --git a/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddVM.kt b/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddVM.kt
index 2f9d1e42..21d0eb24 100644
--- a/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddVM.kt
+++ b/feature-add/src/main/java/com/hoc/flowmvi/ui/add/AddVM.kt
@@ -2,7 +2,6 @@ package com.hoc.flowmvi.ui.add
 
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.viewModelScope
-import arrow.core.orNull
 import com.hoc.flowmvi.domain.model.User
 import com.hoc.flowmvi.domain.usecase.AddUserUseCase
 import com.hoc.flowmvi.mvi_base.AbstractMviViewModel
@@ -82,7 +81,7 @@ class AddVM(
         email = email,
         firstName = firstName,
         lastName = lastName,
-        userValidatedNes = User.create(
+        userEitherNes = User.create(
           email = email,
           firstName = firstName,
           lastName = lastName,
@@ -118,9 +117,9 @@ class AddVM(
     )
 
   private fun Flow<ViewIntent.Submit>.toAddUserChangeFlow(userFormFlow: SharedFlow<PartialStateChange.UserFormState>): Flow<PartialStateChange.AddUser> =
-    withLatestFrom(userFormFlow) { _, userForm -> userForm.userValidatedNes }
+    withLatestFrom(userFormFlow) { _, userForm -> userForm.userEitherNes }
       .debugLog("toAddUserChangeFlow::userValidatedNel")
-      .mapNotNull { it.orNull() }
+      .mapNotNull { it.getOrNull() }
       .flatMapFirst { user ->
         flowFromSuspend { addUser(user) }
           .map { result ->
diff --git a/feature-add/src/test/java/com/hoc/flowmvi/ui/add/AddVMTest.kt b/feature-add/src/test/java/com/hoc/flowmvi/ui/add/AddVMTest.kt
index b7b5a7a1..9e8bf1b0 100644
--- a/feature-add/src/test/java/com/hoc/flowmvi/ui/add/AddVMTest.kt
+++ b/feature-add/src/test/java/com/hoc/flowmvi/ui/add/AddVMTest.kt
@@ -12,7 +12,7 @@ import com.hoc.flowmvi.domain.usecase.AddUserUseCase
 import com.hoc.flowmvi.mvi_testing.BaseMviViewModelTest
 import com.hoc.flowmvi.mvi_testing.mapRight
 import com.hoc.flowmvi.mvi_testing.returnsWithDelay
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import io.mockk.coEvery
 import io.mockk.coVerify
 import io.mockk.confirmVerified
@@ -165,7 +165,7 @@ class AddVMTest : BaseMviViewModelTest<ViewIntent, ViewState, SingleEvent, AddVM
       firstName = NAME,
       lastName = NAME,
       avatar = ""
-    ).valueOrThrow
+    ).rightValueOrThrow
 
     coEvery { addUser(user) } returnsWithDelay Unit.right()
 
@@ -225,7 +225,7 @@ class AddVMTest : BaseMviViewModelTest<ViewIntent, ViewState, SingleEvent, AddVM
       firstName = NAME,
       lastName = NAME,
       avatar = ""
-    ).valueOrThrow
+    ).rightValueOrThrow
     val networkError = UserError.NetworkError
 
     coEvery { addUser(user) } returnsWithDelay networkError.left()
diff --git a/feature-main/src/main/java/com/hoc/flowmvi/ui/main/MainContract.kt b/feature-main/src/main/java/com/hoc/flowmvi/ui/main/MainContract.kt
index 483a2c8e..b6ed064c 100644
--- a/feature-main/src/main/java/com/hoc/flowmvi/ui/main/MainContract.kt
+++ b/feature-main/src/main/java/com/hoc/flowmvi/ui/main/MainContract.kt
@@ -33,7 +33,7 @@ data class UserItem(
     firstName = firstName,
     avatar = avatar,
     email = email
-  ).toEither().mapLeft { UserError.ValidationFailed(it.toSet()) }
+  ).mapLeft { UserError.ValidationFailed(it) }
 }
 
 sealed interface ViewIntent : MviIntent {
diff --git a/feature-main/src/test/java/com/hoc/flowmvi/ui/main/MainContractTest.kt b/feature-main/src/test/java/com/hoc/flowmvi/ui/main/MainContractTest.kt
index 415f4592..a2480d2f 100644
--- a/feature-main/src/test/java/com/hoc/flowmvi/ui/main/MainContractTest.kt
+++ b/feature-main/src/test/java/com/hoc/flowmvi/ui/main/MainContractTest.kt
@@ -1,8 +1,7 @@
 package com.hoc.flowmvi.ui.main
 
 import com.hoc.flowmvi.domain.model.User
-import com.hoc.flowmvi.test_utils.getOrThrow
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -70,14 +69,14 @@ class MainContractTest {
         firstName = "first",
         lastName = "last",
         avatar = "avatar.png",
-      ).valueOrThrow,
+      ).rightValueOrThrow,
       UserItem(
         id = "0",
         email = "test@gmail.com",
         avatar = "avatar.png",
         firstName = "first",
         lastName = "last"
-      ).toDomain().getOrThrow,
+      ).toDomain().rightValueOrThrow,
     )
   }
 
@@ -98,7 +97,7 @@ class MainContractTest {
           firstName = "first",
           lastName = "last",
           avatar = "avatar.png",
-        ).valueOrThrow
+        ).rightValueOrThrow
       ),
     )
   }
diff --git a/feature-main/src/test/java/com/hoc/flowmvi/ui/main/TestData.kt b/feature-main/src/test/java/com/hoc/flowmvi/ui/main/TestData.kt
index ce186154..90730c48 100644
--- a/feature-main/src/test/java/com/hoc/flowmvi/ui/main/TestData.kt
+++ b/feature-main/src/test/java/com/hoc/flowmvi/ui/main/TestData.kt
@@ -1,7 +1,7 @@
 package com.hoc.flowmvi.ui.main
 
 import com.hoc.flowmvi.domain.model.User
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 
 internal val USERS = listOf(
   User.create(
@@ -25,6 +25,6 @@ internal val USERS = listOf(
     lastName = "last3",
     avatar = "3.png"
   ),
-).map { it.valueOrThrow }
+).map { it.rightValueOrThrow }
 
 internal val USER_ITEMS = USERS.map(::UserItem)
diff --git a/feature-search/build.gradle.kts b/feature-search/build.gradle.kts
index d236e8e0..70a3be7a 100644
--- a/feature-search/build.gradle.kts
+++ b/feature-search/build.gradle.kts
@@ -1,7 +1,7 @@
 plugins {
   androidLib
   kotlinAndroid
-  nocopyPlugin
+  pokoPlugin
 }
 
 android {
diff --git a/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchAdapter.kt b/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchAdapter.kt
index 2e2dfe4b..4996208e 100644
--- a/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchAdapter.kt
+++ b/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchAdapter.kt
@@ -1,5 +1,6 @@
 package com.hoc.flowmvi.ui.search
 
+import android.annotation.SuppressLint
 import android.view.ViewGroup
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
@@ -11,6 +12,8 @@ import com.hoc081098.viewbindingdelegate.inflateViewBinding
 internal class SearchAdapter :
   ListAdapter<UserItem, SearchAdapter.VH>(object : DiffUtil.ItemCallback<UserItem>() {
     override fun areItemsTheSame(oldItem: UserItem, newItem: UserItem) = oldItem.id == newItem.id
+
+    @SuppressLint("DiffUtilEquals") // `==` is generated by Poko plugin.
     override fun areContentsTheSame(oldItem: UserItem, newItem: UserItem) = oldItem == newItem
   }) {
 
diff --git a/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchContract.kt b/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchContract.kt
index f4399a4c..546dd88f 100644
--- a/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchContract.kt
+++ b/feature-search/src/main/java/com/hoc/flowmvi/ui/search/SearchContract.kt
@@ -8,11 +8,9 @@ import com.hoc.flowmvi.mvi_base.MviIntent
 import com.hoc.flowmvi.mvi_base.MviSingleEvent
 import com.hoc.flowmvi.mvi_base.MviViewState
 import com.hoc.flowmvi.mvi_base.MviViewStateSaver
-import dev.ahmedmourad.nocopy.annotations.NoCopy
+import dev.drewhamilton.poko.Poko
 
-@Suppress("DataClassPrivateConstructor")
-@NoCopy
-data class UserItem private constructor(
+@Poko class UserItem private constructor(
   val id: String,
   val email: String,
   val avatar: String,
diff --git a/feature-search/src/test/java/com/hoc/flowmvi/ui/search/SearchContractTest.kt b/feature-search/src/test/java/com/hoc/flowmvi/ui/search/SearchContractTest.kt
index 907091c9..aa5310ba 100644
--- a/feature-search/src/test/java/com/hoc/flowmvi/ui/search/SearchContractTest.kt
+++ b/feature-search/src/test/java/com/hoc/flowmvi/ui/search/SearchContractTest.kt
@@ -1,7 +1,7 @@
 package com.hoc.flowmvi.ui.search
 
 import com.hoc.flowmvi.domain.model.User
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -44,6 +44,6 @@ class SearchContractTest {
       avatar = AVATAR,
       firstName = FIRST_NAME,
       lastName = LAST_NAME
-    ).valueOrThrow
+    ).rightValueOrThrow
   }
 }
diff --git a/feature-search/src/test/java/com/hoc/flowmvi/ui/search/TestData.kt b/feature-search/src/test/java/com/hoc/flowmvi/ui/search/TestData.kt
index 256ea616..42268882 100644
--- a/feature-search/src/test/java/com/hoc/flowmvi/ui/search/TestData.kt
+++ b/feature-search/src/test/java/com/hoc/flowmvi/ui/search/TestData.kt
@@ -1,7 +1,7 @@
 package com.hoc.flowmvi.ui.search
 
 import com.hoc.flowmvi.domain.model.User
-import com.hoc.flowmvi.test_utils.valueOrThrow
+import com.hoc.flowmvi.test_utils.rightValueOrThrow
 
 internal val USERS = listOf(
   User.create(
@@ -25,6 +25,6 @@ internal val USERS = listOf(
     lastName = "last3",
     avatar = "3.png"
   ),
-).map { it.valueOrThrow }
+).map { it.rightValueOrThrow }
 
 internal val USER_ITEMS = USERS.map(UserItem::from)
diff --git a/test-utils/src/main/java/com/hoc/flowmvi/test_utils/utils.kt b/test-utils/src/main/java/com/hoc/flowmvi/test_utils/utils.kt
index 1f09c584..9d1465b7 100644
--- a/test-utils/src/main/java/com/hoc/flowmvi/test_utils/utils.kt
+++ b/test-utils/src/main/java/com/hoc/flowmvi/test_utils/utils.kt
@@ -1,24 +1,11 @@
 package com.hoc.flowmvi.test_utils
 
 import arrow.core.Either
-import arrow.core.Validated
-import arrow.core.getOrHandle
+import arrow.core.getOrElse
 import arrow.core.identity
-import arrow.core.valueOr
 
-inline val <E, A> Validated<E, A>.valueOrThrow: A
-  get() = valueOr(this::throws)
+inline val <L, R> Either<L, R>.leftValueOrThrow: L
+  get() = fold(::identity) { throw AssertionError("Expect a Left but got a $this") }
 
-inline val <E, A> Validated<E, A>.invalidValueOrThrow: E
-  get() = fold(::identity, this::throws)
-
-inline val <L, R> Either<L, R>.leftOrThrow: L
-  get() = fold(::identity, this::throws)
-
-inline val <L, R> Either<L, R>.getOrThrow: R
-  get() = getOrHandle(this::throws)
-
-@PublishedApi
-internal fun <E> Any.throws(it: E): Nothing =
-  if (it is Throwable) throw it
-  else error("$this - $it - Should not reach here!")
+inline val <L, R> Either<L, R>.rightValueOrThrow: R
+  get() = getOrElse { throw AssertionError("Expect a Right but got a $this") }