diff --git a/Libraries.xctestplan b/Libraries.xctestplan
new file mode 100644
index 0000000..67792eb
--- /dev/null
+++ b/Libraries.xctestplan
@@ -0,0 +1,24 @@
+{
+  "configurations" : [
+    {
+      "id" : "BF43DE96-4FFB-475F-B056-3EE94ACD1F54",
+      "name" : "Test Scheme Action",
+      "options" : {
+
+      }
+    }
+  ],
+  "defaultOptions" : {
+    "codeCoverage" : false
+  },
+  "testTargets" : [
+    {
+      "target" : {
+        "containerPath" : "container:Libraries",
+        "identifier" : "ReviewsFoundationTest",
+        "name" : "ReviewsFoundationTest"
+      }
+    }
+  ],
+  "version" : 1
+}
diff --git a/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsFoundationTest.xcscheme b/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsFoundationTest.xcscheme
new file mode 100644
index 0000000..212da11
--- /dev/null
+++ b/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsFoundationTest.xcscheme
@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1530"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "ReviewsFoundationTest"
+               BuildableName = "ReviewsFoundationTest"
+               BlueprintName = "ReviewsFoundationTest"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsKit.xcscheme b/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsKit.xcscheme
new file mode 100644
index 0000000..6b81aea
--- /dev/null
+++ b/Libraries/.swiftpm/xcode/xcshareddata/xcschemes/ReviewsKit.xcscheme
@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1530"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "ReviewsKit"
+               BuildableName = "ReviewsKit"
+               BlueprintName = "ReviewsKit"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <TestPlans>
+         <TestPlanReference
+            reference = "container:../Libraries.xctestplan"
+            default = "YES">
+         </TestPlanReference>
+      </TestPlans>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "ReviewsKit"
+            BuildableName = "ReviewsKit"
+            BlueprintName = "ReviewsKit"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/Libraries/Foundation/Kit/Sources/Extensions/String+Constants.swift b/Libraries/Foundation/Kit/Sources/Extensions/String+Constants.swift
new file mode 100644
index 0000000..ab80392
--- /dev/null
+++ b/Libraries/Foundation/Kit/Sources/Extensions/String+Constants.swift
@@ -0,0 +1,18 @@
+//
+//  String+Constants.swift
+//  ReviewsFoundation
+//
+//  Created by Javier Cicchelli on 16/03/2024.
+//  Copyright © 2024 Röck+Cöde VoF. All rights reserved.
+//
+
+import Foundation
+
+public extension String {
+    
+    // MARK: Constants
+    
+    /// A representation of an empty string.
+    static let empty: String = ""
+    
+}
diff --git a/Libraries/Foundation/Test/Tests/Extensions/String+ConstantsTests.swift b/Libraries/Foundation/Test/Tests/Extensions/String+ConstantsTests.swift
new file mode 100644
index 0000000..fcd80c7
--- /dev/null
+++ b/Libraries/Foundation/Test/Tests/Extensions/String+ConstantsTests.swift
@@ -0,0 +1,27 @@
+//
+//  String+ConstantsTests.swift
+//  ReviewsFoundationTest
+//
+//  Created by Javier Cicchelli on 16/03/2024.
+//  Copyright © 2024 Röck+Cöde VoF. All rights reserved.
+//
+
+import ReviewsFoundation
+import XCTest
+
+final class String_ConstantsTests: XCTestCase {
+    
+    // MARK: Properties
+    private var sut: String!
+    
+    // MARK: Constants tests
+    func testEmpty() throws {
+        // GIVEN
+        sut = .empty
+
+        // WHEN
+        // THEN
+        XCTAssertTrue(sut.isEmpty)
+    }
+    
+}
diff --git a/Libraries/Package.swift b/Libraries/Package.swift
new file mode 100644
index 0000000..2fa99db
--- /dev/null
+++ b/Libraries/Package.swift
@@ -0,0 +1,57 @@
+// swift-tools-version: 5.10
+
+import PackageDescription
+
+let package = Package(
+    name: .Package.name,
+    platforms: [
+        .iOS(.v14)
+    ],
+    products: [
+        .library(
+            name: .Product.name.kit,
+            targets: [
+                .Target.foundation
+            ]
+        ),
+    ],
+    targets: [
+        .target(
+            name: .Target.foundation,
+            path: "Foundation/Kit"
+        ),
+        .testTarget(
+            name: .Target.foundation.test,
+            dependencies: [
+                .byName(name: .Target.foundation)
+            ],
+            path: "Foundation/Test"
+        ),
+    ]
+)
+
+// MARK: - String+Constants
+private extension String {
+    enum Package {
+        static let name = "reviews-kit"
+    }
+    
+    enum Product {
+        static let name = "Reviews"
+    }
+    
+    enum Target {
+        static let foundation = "\(String.Product.name)Foundation"
+    }
+}
+
+// MARK: - String+Computed
+private extension String {
+    var kit: String {
+        "\(self)Kit"
+    }
+    
+    var test: String {
+        "\(self)Test"
+    }
+}
diff --git a/Reviews.xcodeproj/project.pbxproj b/Reviews.xcodeproj/project.pbxproj
index 0c43e56..4feecf0 100644
--- a/Reviews.xcodeproj/project.pbxproj
+++ b/Reviews.xcodeproj/project.pbxproj
@@ -14,6 +14,8 @@
 		02DC7FAD2BA51B4C000EEEBE /* ReviewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = 345AD13024C6EE64004E2EE1 /* ReviewCell.swift */; };
 		02DC7FAE2BA51B4C000EEEBE /* FeedViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 345AD12F24C6EE64004E2EE1 /* FeedViewController.swift */; };
 		02DC7FAF2BA51B4C000EEEBE /* Review.swift in Sources */ = {isa = PBXBuildFile; fileRef = 345AD13124C6EE64004E2EE1 /* Review.swift */; };
+		02DC7FB32BA52518000EEEBE /* ReviewsKit in Frameworks */ = {isa = PBXBuildFile; productRef = 02DC7FB22BA52518000EEEBE /* ReviewsKit */; };
+		02DC7FB52BA52520000EEEBE /* ReviewsKit in Frameworks */ = {isa = PBXBuildFile; productRef = 02DC7FB42BA52520000EEEBE /* ReviewsKit */; };
 		345AD11C24C6EDD9004E2EE1 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 345AD11B24C6EDD9004E2EE1 /* AppDelegate.swift */; };
 		345AD12524C6EDDC004E2EE1 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 345AD12424C6EDDC004E2EE1 /* Assets.xcassets */; };
 		345AD12824C6EDDC004E2EE1 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 345AD12624C6EDDC004E2EE1 /* LaunchScreen.storyboard */; };
@@ -44,8 +46,10 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		02900C492BA530E6008D2E8D /* Libraries.xctestplan */ = {isa = PBXFileReference; lastKnownFileType = text; path = Libraries.xctestplan; sourceTree = "<group>"; };
 		02DC7F8F2BA51793000EEEBE /* ReviewsFeed.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = ReviewsFeed.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		02DC7F912BA51793000EEEBE /* ReviewsFeed.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ReviewsFeed.h; sourceTree = "<group>"; };
+		02DC7FB12BA52084000EEEBE /* Libraries */ = {isa = PBXFileReference; lastKnownFileType = wrapper; path = Libraries; sourceTree = "<group>"; };
 		345AD11824C6EDD9004E2EE1 /* Reviews.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Reviews.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		345AD11B24C6EDD9004E2EE1 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		345AD12424C6EDDC004E2EE1 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
@@ -62,6 +66,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				02DC7FB32BA52518000EEEBE /* ReviewsKit in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -70,12 +75,21 @@
 			buildActionMask = 2147483647;
 			files = (
 				02DC7FA22BA51793000EEEBE /* ReviewsFeed.framework in Frameworks */,
+				02DC7FB52BA52520000EEEBE /* ReviewsKit in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		02900C4A2BA53162008D2E8D /* Test Plans */ = {
+			isa = PBXGroup;
+			children = (
+				02900C492BA530E6008D2E8D /* Libraries.xctestplan */,
+			);
+			name = "Test Plans";
+			sourceTree = "<group>";
+		};
 		02DC7F722BA4F8F0000EEEBE /* Resources */ = {
 			isa = PBXGroup;
 			children = (
@@ -149,8 +163,10 @@
 		345AD10F24C6EDD9004E2EE1 = {
 			isa = PBXGroup;
 			children = (
+				02DC7FB12BA52084000EEEBE /* Libraries */,
 				02DC7FAB2BA51848000EEEBE /* Frameworks */,
 				345AD11A24C6EDD9004E2EE1 /* App */,
+				02900C4A2BA53162008D2E8D /* Test Plans */,
 				345AD11924C6EDD9004E2EE1 /* Products */,
 			);
 			sourceTree = "<group>";
@@ -201,6 +217,9 @@
 			dependencies = (
 			);
 			name = Feed;
+			packageProductDependencies = (
+				02DC7FB22BA52518000EEEBE /* ReviewsKit */,
+			);
 			productName = Feed;
 			productReference = 02DC7F8F2BA51793000EEEBE /* ReviewsFeed.framework */;
 			productType = "com.apple.product-type.framework";
@@ -220,6 +239,9 @@
 				02DC7FA12BA51793000EEEBE /* PBXTargetDependency */,
 			);
 			name = App;
+			packageProductDependencies = (
+				02DC7FB42BA52520000EEEBE /* ReviewsKit */,
+			);
 			productName = AppStoreReviews;
 			productReference = 345AD11824C6EDD9004E2EE1 /* Reviews.app */;
 			productType = "com.apple.product-type.application";
@@ -625,6 +647,17 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCSwiftPackageProductDependency section */
+		02DC7FB22BA52518000EEEBE /* ReviewsKit */ = {
+			isa = XCSwiftPackageProductDependency;
+			productName = ReviewsKit;
+		};
+		02DC7FB42BA52520000EEEBE /* ReviewsKit */ = {
+			isa = XCSwiftPackageProductDependency;
+			productName = ReviewsKit;
+		};
+/* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = 345AD11024C6EDD9004E2EE1 /* Project object */;
 }