diff --git a/Projects/DVData/Sources/RepositoryImpl/Settings/SettingsRepositoryImpl.swift b/Projects/DVData/Sources/RepositoryImpl/Settings/SettingsRepositoryImpl.swift
new file mode 100644
index 00000000..a0292813
--- /dev/null
+++ b/Projects/DVData/Sources/RepositoryImpl/Settings/SettingsRepositoryImpl.swift
@@ -0,0 +1,22 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+import DVDomain
+
+// UserDefaults는 thread-safe하므로 @unchecked Sendable 허용
+public struct SettingsRepositoryImpl: SettingsRepository, @unchecked Sendable {
+
+  private let defaults: UserDefaults
+
+  public init(defaults: UserDefaults = .standard) {
+    self.defaults = defaults
+  }
+
+  public func hasCompletedOnboarding() -> Bool {
+    defaults.bool(forKey: .hasCompletedOnboarding)
+  }
+
+  public func setOnboardingCompleted() {
+    defaults.set(true, forKey: .hasCompletedOnboarding)
+  }
+}
diff --git a/Projects/DVData/Sources/RepositoryImpl/Settings/UserDefaultsKey.swift b/Projects/DVData/Sources/RepositoryImpl/Settings/UserDefaultsKey.swift
new file mode 100644
index 00000000..8a4907a8
--- /dev/null
+++ b/Projects/DVData/Sources/RepositoryImpl/Settings/UserDefaultsKey.swift
@@ -0,0 +1,17 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+enum UserDefaultsKey: String {
+  case hasCompletedOnboarding
+}
+
+extension UserDefaults {
+  func bool(forKey key: UserDefaultsKey) -> Bool {
+    bool(forKey: key.rawValue)
+  }
+
+  func set(_ value: Bool, forKey key: UserDefaultsKey) {
+    set(value, forKey: key.rawValue)
+  }
+}
diff --git a/Projects/DVDesign/Sources/Foundations/Color/View+DVColor.swift b/Projects/DVDesign/Sources/Foundations/Color/View+DVColor.swift
index d8f02244..1a255cba 100644
--- a/Projects/DVDesign/Sources/Foundations/Color/View+DVColor.swift
+++ b/Projects/DVDesign/Sources/Foundations/Color/View+DVColor.swift
@@ -2,16 +2,16 @@
 
 import SwiftUI
 
-public extension View {
-    func dvForegroundColor(_ token: DVColor) -> some View {
+extension View {
+    public func dvForegroundColor(_ token: DVColor) -> some View {
         self.foregroundStyle(token.color)
     }
 
-    func dvBackgroundColor(_ token: DVColor) -> some View {
+    public func dvBackgroundColor(_ token: DVColor) -> some View {
         self.background(token.color)
     }
 
-    func dvScreenBackground(_ token: DVColor = .gray100) -> some View {
+    public func dvScreenBackground(_ token: DVColor = .gray100) -> some View {
         self.background(token.color.ignoresSafeArea())
     }
 }
diff --git a/Projects/DVDomain/Sources/Repository/Interface/SettingsRepository.swift b/Projects/DVDomain/Sources/Repository/Interface/SettingsRepository.swift
new file mode 100644
index 00000000..2f1a6587
--- /dev/null
+++ b/Projects/DVDomain/Sources/Repository/Interface/SettingsRepository.swift
@@ -0,0 +1,8 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+public protocol SettingsRepository: Sendable {
+  func hasCompletedOnboarding() -> Bool
+  func setOnboardingCompleted()
+}
diff --git a/Projects/DVDomain/Sources/UseCase/Impl/Settings/OnboardingStatusUseCaseImpl.swift b/Projects/DVDomain/Sources/UseCase/Impl/Settings/OnboardingStatusUseCaseImpl.swift
new file mode 100644
index 00000000..8b25acb4
--- /dev/null
+++ b/Projects/DVDomain/Sources/UseCase/Impl/Settings/OnboardingStatusUseCaseImpl.swift
@@ -0,0 +1,20 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+public struct OnboardingStatusUseCaseImpl: OnboardingStatusUseCase {
+
+  private let repository: any SettingsRepository
+
+  public init(repository: any SettingsRepository) {
+    self.repository = repository
+  }
+
+  public func hasCompleted() -> Bool {
+    repository.hasCompletedOnboarding()
+  }
+
+  public func setCompleted() {
+    repository.setOnboardingCompleted()
+  }
+}
diff --git a/Projects/DVDomain/Sources/UseCase/Interface/Settings/OnboardingStatusUseCase.swift b/Projects/DVDomain/Sources/UseCase/Interface/Settings/OnboardingStatusUseCase.swift
new file mode 100644
index 00000000..26998174
--- /dev/null
+++ b/Projects/DVDomain/Sources/UseCase/Interface/Settings/OnboardingStatusUseCase.swift
@@ -0,0 +1,8 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+public protocol OnboardingStatusUseCase: Sendable {
+  func hasCompleted() -> Bool
+  func setCompleted()
+}
diff --git a/Projects/DVPresentation/Project.swift b/Projects/DVPresentation/Project.swift
index c0bd94e6..7ef86892 100644
--- a/Projects/DVPresentation/Project.swift
+++ b/Projects/DVPresentation/Project.swift
@@ -17,6 +17,7 @@ let project = Project.project(
 
                 // 3rd-party dependency
                 .tca(),
+                .lottie(),
             ]
         ),
         .tests(
diff --git a/Projects/DVPresentation/Resources/Localizable.xcstrings b/Projects/DVPresentation/Resources/Localizable.xcstrings
index 966dec69..91840cfb 100644
--- a/Projects/DVPresentation/Resources/Localizable.xcstrings
+++ b/Projects/DVPresentation/Resources/Localizable.xcstrings
@@ -1,39 +1,59 @@
 {
   "sourceLanguage" : "en",
   "strings" : {
+    "Access your secrets on all your\nApple devices, securely encrypted." : {
+
+    },
     "Content" : {
       "comment" : "The title of the main content section in the preview.",
       "isCommentAutoGenerated" : true
+    },
+    "Create Project" : {
+
+    },
+    "De" : {
+
     },
     "Detail" : {
 
     },
-    "Development" : {
+    "If Touch ID is unavailable,\nsystem password will be used" : {
 
     },
-    "Enterprise" : {
+    "LOGO" : {
 
     },
-    "Failed to load projects" : {
+    "No expire" : {
 
     },
-    "Individual" : {
+    "Placeholder row %@" : {
 
     },
-    "Production" : {
+    "Project" : {
 
     },
-    "Staging" : {
+    "Project Name" : {
 
     },
-    "Team" : {
+    "Save" : {
 
     },
-    "Sidebar" : {
-      "comment" : "The text that appears in the sidebar of the main view.",
-      "isCommentAutoGenerated" : true
+    "Select Project" : {
+
+    },
+    "SSL Required" : {
+
+    },
+    "This may take a moment..." : {
+
+    },
+    "Vault" : {
+
+    },
+    "목록을 불러오지 못했어요" : {
+
     },
-    "The project list couldn't be loaded. Please try again later." : {
+    "시크릿이 없어요" : {
 
     }
   },
diff --git a/Projects/DVPresentation/Sources/Dependencies/OnboardingStatusClient.swift b/Projects/DVPresentation/Sources/Dependencies/OnboardingStatusClient.swift
new file mode 100644
index 00000000..8435f847
--- /dev/null
+++ b/Projects/DVPresentation/Sources/Dependencies/OnboardingStatusClient.swift
@@ -0,0 +1,33 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+import ComposableArchitecture
+
+// MARK: - OnboardingStatusClient
+
+@DependencyClient
+public struct OnboardingStatusClient {
+  public var hasCompleted: @Sendable () -> Bool = { false }
+  public var setCompleted: @Sendable () -> Void
+}
+
+// MARK: - DependencyKey
+
+extension OnboardingStatusClient: TestDependencyKey {
+  public static let testValue = OnboardingStatusClient()
+
+  public static let previewValue = OnboardingStatusClient(
+    hasCompleted: { false },
+    setCompleted: { }
+  )
+}
+
+// MARK: - DependencyValues
+
+extension DependencyValues {
+  public var onboardingStatus: OnboardingStatusClient {
+    get { self[OnboardingStatusClient.self] }
+    set { self[OnboardingStatusClient.self] = newValue }
+  }
+}
diff --git a/Projects/DVPresentation/Sources/Features/AppFeature.swift b/Projects/DVPresentation/Sources/Features/AppFeature.swift
index 66ad6ebf..84bba50d 100644
--- a/Projects/DVPresentation/Sources/Features/AppFeature.swift
+++ b/Projects/DVPresentation/Sources/Features/AppFeature.swift
@@ -1,6 +1,6 @@
 // Copyright © 2026 Devault. All rights reserved
 
-import SwiftUI
+import Foundation
 
 import ComposableArchitecture
 
@@ -13,7 +13,10 @@ public struct AppFeature {
 
   @ObservableState
   public struct State: Equatable {
-    var main: MainFeature.State = .init()
+    // 세 프로퍼티 중 항상 하나만 non-nil — reducer 로직으로 불변식 보장
+    var onboarding: OnboardingContainerFeature.State?
+    var locked: LockFeature.State?
+    var main: MainFeature.State?
 
     public init() {}
   }
@@ -28,6 +31,8 @@ public struct AppFeature {
 
     // MARK: - Child
 
+    case onboarding(OnboardingContainerFeature.Action)
+    case locked(LockFeature.Action)
     case main(MainFeature.Action)
 
     // MARK: - Delegate
@@ -37,6 +42,10 @@ public struct AppFeature {
     public enum Delegate: Equatable {}
   }
 
+  // MARK: - Dependencies
+
+  @Dependency(\.onboardingStatus) var onboardingStatus
+
   // MARK: - Init
 
   public init() {}
@@ -44,12 +53,34 @@ public struct AppFeature {
   // MARK: - Body
 
   public var body: some ReducerOf<Self> {
-    Scope(state: \.main, action: \.main) {
-      MainFeature()
-    }
     Reduce { state, action in
       switch action {
       case .task:
+        state.onboarding = nil
+        state.locked = nil
+        state.main = nil
+
+        if onboardingStatus.hasCompleted() {
+          state.locked = .init()
+        } else {
+          state.onboarding = .init()
+        }
+        return .none
+
+      case .onboarding(.delegate(.completed)):
+        state.onboarding = nil
+        state.main = .init()
+        return .run { _ in onboardingStatus.setCompleted() }
+
+      case .onboarding:
+        return .none
+
+      case .locked(.delegate(.unlockCompleted)):
+        state.locked = nil
+        state.main = .init()
+        return .none
+
+      case .locked:
         return .none
 
       case .main:
@@ -59,5 +90,14 @@ public struct AppFeature {
         return .none
       }
     }
+    .ifLet(\.onboarding, action: \.onboarding) {
+      OnboardingContainerFeature()
+    }
+    .ifLet(\.locked, action: \.locked) {
+      LockFeature()
+    }
+    .ifLet(\.main, action: \.main) {
+      MainFeature()
+    }
   }
 }
diff --git a/Projects/DVPresentation/Sources/Features/AppView.swift b/Projects/DVPresentation/Sources/Features/AppView.swift
index 41c80426..47093e21 100644
--- a/Projects/DVPresentation/Sources/Features/AppView.swift
+++ b/Projects/DVPresentation/Sources/Features/AppView.swift
@@ -10,7 +10,7 @@ public struct AppView: View {
 
   // MARK: - Properties
 
-  @Bindable public var store: StoreOf<AppFeature>
+  @Bindable var store: StoreOf<AppFeature>
 
   // MARK: - Init
 
@@ -30,8 +30,15 @@ public struct AppView: View {
 
 extension AppView {
 
+  @ViewBuilder
   private var content: some View {
-    MainView(store: store.scope(state: \.main, action: \.main))
+    if let store = store.scope(state: \.onboarding, action: \.onboarding) {
+      OnboardingContainerView(store: store)
+    } else if let store = store.scope(state: \.locked, action: \.locked) {
+      LockView(store: store)
+    } else if let store = store.scope(state: \.main, action: \.main) {
+      MainView(store: store)
+    }
   }
 }
 
@@ -41,6 +48,9 @@ extension AppView {
   AppView(
     store: Store(initialState: AppFeature.State()) {
       AppFeature()
+    } withDependencies: {
+      $0.onboardingStatus.hasCompleted = { false }
+      $0.onboardingStatus.setCompleted = { }
     }
   )
 }
diff --git a/Projects/DVPresentation/Sources/Features/Lock/LockFeature.swift b/Projects/DVPresentation/Sources/Features/Lock/LockFeature.swift
index de89e18f..9c12d1cc 100644
--- a/Projects/DVPresentation/Sources/Features/Lock/LockFeature.swift
+++ b/Projects/DVPresentation/Sources/Features/Lock/LockFeature.swift
@@ -13,11 +13,7 @@ public struct LockFeature {
 
   @ObservableState
   public struct State: Equatable {
-    public var isPostOnboarding: Bool
-
-    public init(isPostOnboarding: Bool = false) {
-      self.isPostOnboarding = isPostOnboarding
-    }
+    public init() {}
   }
 
   // MARK: - Action
diff --git a/Projects/DVPresentation/Sources/Features/Lock/LockView.swift b/Projects/DVPresentation/Sources/Features/Lock/LockView.swift
index bf522c64..2a7c3e60 100644
--- a/Projects/DVPresentation/Sources/Features/Lock/LockView.swift
+++ b/Projects/DVPresentation/Sources/Features/Lock/LockView.swift
@@ -11,7 +11,7 @@ public struct LockView: View {
 
   // MARK: - Properties
 
-  @Bindable public var store: StoreOf<LockFeature>
+  @Bindable var store: StoreOf<LockFeature>
 
   // MARK: - Init
 
@@ -32,17 +32,8 @@ public struct LockView: View {
 extension LockView {
 
   private var content: some View {
-    ZStack {
-      unlockView
-      if store.isPostOnboarding {
-        VStack {
-          Spacer()
-          DVStepIndicator(totalSteps: 4, currentStep: 3)
-            .padding(.bottom, 40)
-        }
-      }
-    }
-    .frame(maxWidth: .infinity, maxHeight: .infinity)
+    unlockView
+      .frame(maxWidth: .infinity, maxHeight: .infinity)
   }
 
   private var unlockView: some View {
@@ -70,18 +61,9 @@ extension LockView {
 
 // MARK: - Preview
 
-#Preview("Post Onboarding") {
-  LockView(
-    store: Store(initialState: LockFeature.State(isPostOnboarding: true)) {
-      LockFeature()
-    }
-  )
-  .frame(width: 540, height: 400)
-}
-
-#Preview("Re-entry / Locked") {
+#Preview {
   LockView(
-    store: Store(initialState: LockFeature.State(isPostOnboarding: false)) {
+    store: Store(initialState: LockFeature.State()) {
       LockFeature()
     }
   )
diff --git a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerFeature.swift b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerFeature.swift
new file mode 100644
index 00000000..3f58cf9f
--- /dev/null
+++ b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerFeature.swift
@@ -0,0 +1,81 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import Foundation
+
+import ComposableArchitecture
+
+// MARK: - OnboardingContainerFeature
+
+@Reducer
+public struct OnboardingContainerFeature {
+
+  // MARK: - State
+
+  @ObservableState
+  public struct State: Equatable {
+    var onboarding: OnboardingFeature.State?
+    var lock: LockFeature.State?
+
+    public init() {
+      self.onboarding = .init()
+    }
+
+    var currentStepIndex: Int {
+      if let onboarding { return onboarding.currentStepIndex }
+      return OnboardingFeature.Step.allCases.count - 1
+    }
+  }
+
+  // MARK: - Action
+
+  public enum Action: Equatable {
+
+    // MARK: - Child
+
+    case onboarding(OnboardingFeature.Action)
+    case lock(LockFeature.Action)
+
+    // MARK: - Delegate
+
+    case delegate(Delegate)
+
+    public enum Delegate: Equatable {
+      case completed
+    }
+  }
+
+  // MARK: - Init
+
+  public init() {}
+
+  // MARK: - Body
+
+  public var body: some ReducerOf<Self> {
+    Reduce { state, action in
+      switch action {
+      case .onboarding(.delegate(.completed)):
+        state.onboarding = nil
+        state.lock = .init()
+        return .none
+
+      case .onboarding:
+        return .none
+
+      case .lock(.delegate(.unlockCompleted)):
+        return .send(.delegate(.completed))
+
+      case .lock:
+        return .none
+
+      case .delegate:
+        return .none
+      }
+    }
+    .ifLet(\.onboarding, action: \.onboarding) {
+      OnboardingFeature()
+    }
+    .ifLet(\.lock, action: \.lock) {
+      LockFeature()
+    }
+  }
+}
diff --git a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerView.swift b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerView.swift
new file mode 100644
index 00000000..33f03d6a
--- /dev/null
+++ b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingContainerView.swift
@@ -0,0 +1,66 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import SwiftUI
+
+import ComposableArchitecture
+import DVDesign
+
+// MARK: - OnboardingContainerView
+
+public struct OnboardingContainerView: View {
+
+  // MARK: - Properties
+
+  @Bindable var store: StoreOf<OnboardingContainerFeature>
+
+  // MARK: - Init
+
+  public init(store: StoreOf<OnboardingContainerFeature>) {
+    self.store = store
+  }
+
+  // MARK: - Body
+
+  public var body: some View {
+    content
+      .dvScreenBackground()
+  }
+}
+
+// MARK: - Subviews
+
+extension OnboardingContainerView {
+    
+  private var content: some View {
+    ZStack {
+      stepView
+      VStack {
+        Spacer()
+        DVStepIndicator(totalSteps: OnboardingFeature.Step.allCases.count, currentStep: store.currentStepIndex)
+          .padding(.bottom, 40)
+      }
+    }
+    .frame(maxWidth: .infinity, maxHeight: .infinity)
+  }
+
+  @ViewBuilder
+  private var stepView: some View {
+    if let store = store.scope(state: \.onboarding, action: \.onboarding) {
+      OnboardingView(store: store)
+    } else if let store = store.scope(state: \.lock, action: \.lock) {
+      LockView(store: store)
+    }
+  }
+}
+
+// MARK: - Preview
+
+#Preview("Onboarding Flow") {
+  OnboardingContainerView(
+    store: Store(initialState: OnboardingContainerFeature.State()) {
+      OnboardingContainerFeature()
+    }
+  )
+  .frame(width: 540, height: 400)
+}
+
diff --git a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingFeature.swift b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingFeature.swift
index a4dbfd57..56fa436e 100644
--- a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingFeature.swift
+++ b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingFeature.swift
@@ -11,7 +11,7 @@ public struct OnboardingFeature {
 
   // MARK: - Step
 
-  public enum Step: Equatable {
+  public enum Step: Equatable, CaseIterable {
     case welcome
     case security
     case icloudSync
@@ -59,6 +59,10 @@ public struct OnboardingFeature {
     }
   }
 
+  // MARK: - Dependencies
+
+  @Dependency(\.continuousClock) var clock
+
   // MARK: - Init
 
   public init() {}
@@ -81,7 +85,11 @@ public struct OnboardingFeature {
 
       case .didTapEnableSync:
         state.step = .syncing
-        return .none
+        return .run { send in
+          // TODO: 실제 iCloud sync 완료 콜백으로 교체
+          try await clock.sleep(for: .seconds(3))
+          await send(.syncingCompleted)
+        }
 
       case .syncingCompleted:
         return .send(.delegate(.completed))
diff --git a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingView.swift b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingView.swift
index 7492dcd8..e60a8cdf 100644
--- a/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingView.swift
+++ b/Projects/DVPresentation/Sources/Features/Onboarding/OnboardingView.swift
@@ -12,7 +12,7 @@ public struct OnboardingView: View {
 
   // MARK: - Properties
 
-  @Bindable public var store: StoreOf<OnboardingFeature>
+  @Bindable var store: StoreOf<OnboardingFeature>
 
   // MARK: - Init
 
@@ -33,15 +33,8 @@ public struct OnboardingView: View {
 extension OnboardingView {
 
   private var content: some View {
-    ZStack {
-      stepContent
-      VStack {
-        Spacer()
-        DVStepIndicator(totalSteps: 4, currentStep: store.currentStepIndex)
-          .padding(.bottom, 40)
-      }
-    }
-    .frame(maxWidth: .infinity, maxHeight: .infinity)
+    stepContent
+      .frame(maxWidth: .infinity, maxHeight: .infinity)
   }
 
   @ViewBuilder
diff --git a/Projects/Devault/Sources/Composition/Dependencies/OnboardingStatusClient+Live.swift b/Projects/Devault/Sources/Composition/Dependencies/OnboardingStatusClient+Live.swift
new file mode 100644
index 00000000..3dbc8971
--- /dev/null
+++ b/Projects/Devault/Sources/Composition/Dependencies/OnboardingStatusClient+Live.swift
@@ -0,0 +1,18 @@
+// Copyright © 2026 Devault. All rights reserved
+
+import ComposableArchitecture
+import DVPresentation
+import DVDomain
+import DVData
+
+extension OnboardingStatusClient: @retroactive DependencyKey {
+  public static let liveValue: OnboardingStatusClient = {
+    let repository: any SettingsRepository = SettingsRepositoryImpl()
+    let useCase: any OnboardingStatusUseCase = OnboardingStatusUseCaseImpl(repository: repository)
+
+    return OnboardingStatusClient(
+      hasCompleted: { useCase.hasCompleted() },
+      setCompleted: { useCase.setCompleted() }
+    )
+  }()
+}
diff --git a/Projects/Devault/Sources/DevaultApp.swift b/Projects/Devault/Sources/DevaultApp.swift
index 69316e6e..8106549b 100644
--- a/Projects/Devault/Sources/DevaultApp.swift
+++ b/Projects/Devault/Sources/DevaultApp.swift
@@ -5,13 +5,16 @@ import DVPresentation
 
 @main
 struct DevaultApp: App {
-    var body: some Scene {
-        WindowGroup {
-            AppView(
-                store: Store(initialState: AppFeature.State()) {
-                    AppFeature()
-                }
-            )
+  var body: some Scene {
+    WindowGroup {
+      AppView(
+        store: Store(initialState: AppFeature.State()) {
+          AppFeature()
         }
+      )
+      .frame(maxWidth: .infinity, maxHeight: .infinity)
     }
+    .windowStyle(.hiddenTitleBar)
+    .defaultSize(width: 800, height: 600)
+  }
 }