diff --git a/HTTP/Sources/Stubbing/StubbingURLProtocol.swift b/HTTP/Sources/Stubbing/StubbingURLProtocol.swift
index 8e62d7a..7d1cc6f 100644
--- a/HTTP/Sources/Stubbing/StubbingURLProtocol.swift
+++ b/HTTP/Sources/Stubbing/StubbingURLProtocol.swift
@@ -3,7 +3,7 @@
 import Foundation
 import HTTP
 
-public class StubbingURLProtocol: URLProtocol {
+public final class StubbingURLProtocol: URLProtocol {
     private static var targetsForURLs = [URL: Target]()
     private static var stubsForURLs = [URL: HTTPStub]()
 
diff --git a/Mastodon/Sources/Mastodon/Entities/HTML.swift b/Mastodon/Sources/Mastodon/Entities/HTML.swift
index e62f4bb..c76caa4 100644
--- a/Mastodon/Sources/Mastodon/Entities/HTML.swift
+++ b/Mastodon/Sources/Mastodon/Entities/HTML.swift
@@ -39,7 +39,7 @@ private extension HTML {
 
 // https://docs.joinmastodon.org/spec/activitypub/#sanitization
 
-private class HTMLParser: NSObject {
+private final class HTMLParser: NSObject {
     private struct Link: Hashable {
         let href: URL
         let location: Int
diff --git a/Notification Service Extension/NotificationService.swift b/Notification Service Extension/NotificationService.swift
index 47c9342..393fb61 100644
--- a/Notification Service Extension/NotificationService.swift	
+++ b/Notification Service Extension/NotificationService.swift	
@@ -6,7 +6,7 @@ import Mastodon
 import Secrets
 import UserNotifications
 
-class NotificationService: UNNotificationServiceExtension {
+final class NotificationService: UNNotificationServiceExtension {
 
     var contentHandler: ((UNNotificationContent) -> Void)?
     var bestAttemptContent: UNMutableNotificationContent?
diff --git a/ServiceLayer/Sources/ServiceLayer/Utilities/UserNotificationClient.swift b/ServiceLayer/Sources/ServiceLayer/Utilities/UserNotificationClient.swift
index 618a543..3e61bf2 100644
--- a/ServiceLayer/Sources/ServiceLayer/Utilities/UserNotificationClient.swift
+++ b/ServiceLayer/Sources/ServiceLayer/Utilities/UserNotificationClient.swift
@@ -27,7 +27,7 @@ public struct UserNotificationClient {
 extension UserNotificationClient {
     public static func live(_ userNotificationCenter: UNUserNotificationCenter) -> Self {
         // swiftlint:disable nesting
-        class Delegate: NSObject, UNUserNotificationCenterDelegate {
+        final class Delegate: NSObject, UNUserNotificationCenterDelegate {
             let subject: PassthroughSubject<DelegateEvent, Never>
 
             init(subject: PassthroughSubject<DelegateEvent, Never>) {
diff --git a/ServiceLayer/Sources/ServiceLayer/Utilities/WebAuthSession.swift b/ServiceLayer/Sources/ServiceLayer/Utilities/WebAuthSession.swift
index 89e4ff0..ee3a689 100644
--- a/ServiceLayer/Sources/ServiceLayer/Utilities/WebAuthSession.swift
+++ b/ServiceLayer/Sources/ServiceLayer/Utilities/WebAuthSession.swift
@@ -42,7 +42,7 @@ extension WebAuthSession {
     }
 }
 
-class WebAuthSessionContextProvider: NSObject, ASWebAuthenticationPresentationContextProviding {
+final class WebAuthSessionContextProvider: NSObject, ASWebAuthenticationPresentationContextProviding {
     func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor {
         ASPresentationAnchor()
     }
diff --git a/ServiceLayer/Sources/ServiceLayerMocks/MockUserDefaults.swift b/ServiceLayer/Sources/ServiceLayerMocks/MockUserDefaults.swift
index cae3c06..cbbba72 100644
--- a/ServiceLayer/Sources/ServiceLayerMocks/MockUserDefaults.swift
+++ b/ServiceLayer/Sources/ServiceLayerMocks/MockUserDefaults.swift
@@ -2,7 +2,7 @@
 
 import Foundation
 
-public class MockUserDefaults: UserDefaults {
+public final class MockUserDefaults: UserDefaults {
     public convenience init() {
         self.init(suiteName: Self.suiteName)!
     }
diff --git a/ServiceLayer/Sources/ServiceLayerMocks/MockWebAuthSession.swift b/ServiceLayer/Sources/ServiceLayerMocks/MockWebAuthSession.swift
index c3ce386..3039b02 100644
--- a/ServiceLayer/Sources/ServiceLayerMocks/MockWebAuthSession.swift
+++ b/ServiceLayer/Sources/ServiceLayerMocks/MockWebAuthSession.swift
@@ -33,7 +33,7 @@ public class MockWebAuthSession: WebAuthSession {
     }
 }
 
-public class SuccessfulMockWebAuthSession: MockWebAuthSession {
+public final class SuccessfulMockWebAuthSession: MockWebAuthSession {
     private let redirectURL: URL
 
     required init(
@@ -60,7 +60,7 @@ public class SuccessfulMockWebAuthSession: MockWebAuthSession {
     }
 }
 
-public class CanceledLoginMockWebAuthSession: MockWebAuthSession {
+public final class CanceledLoginMockWebAuthSession: MockWebAuthSession {
     override var completionHandlerError: Error? {
         WebAuthSessionError(.canceledLogin)
     }
diff --git a/ServiceLayer/Tests/ServiceLayerTests/AuthenticationServiceTests.swift b/ServiceLayer/Tests/ServiceLayerTests/AuthenticationServiceTests.swift
index 1fe8a54..bc8abfc 100644
--- a/ServiceLayer/Tests/ServiceLayerTests/AuthenticationServiceTests.swift
+++ b/ServiceLayer/Tests/ServiceLayerTests/AuthenticationServiceTests.swift
@@ -6,7 +6,7 @@ import CombineExpectations
 @testable import ServiceLayerMocks
 import XCTest
 
-class AuthenticationServiceTests: XCTestCase {
+final class AuthenticationServiceTests: XCTestCase {
     func testAuthentication() throws {
         let sut = AuthenticationService(url: URL(string: "https://mastodon.social")!, environment: .mock())
         let authenticationRecorder = sut.authenticate().record()
diff --git a/ServiceLayer/Tests/ServiceLayerTests/InstanceURLServiceTests.swift b/ServiceLayer/Tests/ServiceLayerTests/InstanceURLServiceTests.swift
index 776805d..d227b07 100644
--- a/ServiceLayer/Tests/ServiceLayerTests/InstanceURLServiceTests.swift
+++ b/ServiceLayer/Tests/ServiceLayerTests/InstanceURLServiceTests.swift
@@ -8,7 +8,7 @@ import CombineExpectations
 import Stubbing
 import XCTest
 
-class InstanceURLServiceTests: XCTestCase {
+final class InstanceURLServiceTests: XCTestCase {
     func testFiltering() throws {
         let sut = InstanceURLService(environment: .mock())
 
diff --git a/Transitions/ZoomAnimator.swift b/Transitions/ZoomAnimator.swift
index bf60a04..5e0b041 100644
--- a/Transitions/ZoomAnimator.swift
+++ b/Transitions/ZoomAnimator.swift
@@ -9,7 +9,7 @@ protocol ZoomAnimatorDelegate: class {
     func referenceViewFrameInTransitioningView(for zoomAnimator: ZoomAnimator) -> CGRect?
 }
 
-class ZoomAnimator: NSObject {
+final class ZoomAnimator: NSObject {
     weak var fromDelegate: ZoomAnimatorDelegate?
     weak var toDelegate: ZoomAnimatorDelegate?
 
diff --git a/Transitions/ZoomDismissalInteractionController.swift b/Transitions/ZoomDismissalInteractionController.swift
index f10b34d..71968fb 100644
--- a/Transitions/ZoomDismissalInteractionController.swift
+++ b/Transitions/ZoomDismissalInteractionController.swift
@@ -2,7 +2,7 @@
 
 import UIKit
 
-class ZoomDismissalInteractionController: NSObject {
+final class ZoomDismissalInteractionController: NSObject {
     var transitionContext: UIViewControllerContextTransitioning?
     var animator: UIViewControllerAnimatedTransitioning?
 
diff --git a/Transitions/ZoomTransitionController.swift b/Transitions/ZoomTransitionController.swift
index 9b81c66..7b5fd64 100644
--- a/Transitions/ZoomTransitionController.swift
+++ b/Transitions/ZoomTransitionController.swift
@@ -2,7 +2,7 @@
 
 import UIKit
 
-class ZoomTransitionController: NSObject {
+final class ZoomTransitionController: NSObject {
     var isInteractive = false
 
     weak var fromDelegate: ZoomAnimatorDelegate?
diff --git a/View Controllers/ImageNavigationController.swift b/View Controllers/ImageNavigationController.swift
index abc50e8..363bc79 100644
--- a/View Controllers/ImageNavigationController.swift	
+++ b/View Controllers/ImageNavigationController.swift	
@@ -3,7 +3,7 @@
 import AVFoundation
 import UIKit
 
-class ImageNavigationController: UINavigationController {
+final class ImageNavigationController: UINavigationController {
     let transitionController = ZoomTransitionController()
 
     private let imagePageViewController: ImagePageViewController
diff --git a/View Controllers/ImagePageViewController.swift b/View Controllers/ImagePageViewController.swift
index 597a604..b654445 100644
--- a/View Controllers/ImagePageViewController.swift	
+++ b/View Controllers/ImagePageViewController.swift	
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class ImagePageViewController: UIPageViewController {
+final class ImagePageViewController: UIPageViewController {
     let imageViewControllers: [ImageViewController]
 
     init(initiallyVisible: AttachmentViewModel, statusViewModel: StatusViewModel) {
diff --git a/View Controllers/ImageViewController.swift b/View Controllers/ImageViewController.swift
index b710b5b..2a04861 100644
--- a/View Controllers/ImageViewController.swift	
+++ b/View Controllers/ImageViewController.swift	
@@ -4,7 +4,7 @@ import Kingfisher
 import UIKit
 import ViewModels
 
-class ImageViewController: UIViewController {
+final class ImageViewController: UIViewController {
     let scrollView = UIScrollView()
     let imageView = AnimatedImageView()
     let playerView = PlayerView()
diff --git a/ViewModels/Sources/ViewModels/CollectionItemsViewModel.swift b/ViewModels/Sources/ViewModels/CollectionItemsViewModel.swift
index dc2e28d..614541e 100644
--- a/ViewModels/Sources/ViewModels/CollectionItemsViewModel.swift
+++ b/ViewModels/Sources/ViewModels/CollectionItemsViewModel.swift
@@ -5,7 +5,7 @@ import Foundation
 import Mastodon
 import ServiceLayer
 
-final public class CollectionItemsViewModel: ObservableObject {
+public final class CollectionItemsViewModel: ObservableObject {
     @Published public var alertItem: AlertItem?
     public private(set) var nextPageMaxId: String?
 
diff --git a/ViewModels/Sources/ViewModels/LoadMoreViewModel.swift b/ViewModels/Sources/ViewModels/LoadMoreViewModel.swift
index 2beb843..d4e3dee 100644
--- a/ViewModels/Sources/ViewModels/LoadMoreViewModel.swift
+++ b/ViewModels/Sources/ViewModels/LoadMoreViewModel.swift
@@ -3,7 +3,7 @@
 import Combine
 import ServiceLayer
 
-final public class LoadMoreViewModel: ObservableObject, CollectionItemViewModel {
+public final class LoadMoreViewModel: ObservableObject, CollectionItemViewModel {
     public var direction = LoadMore.Direction.up
     @Published public private(set) var loading = false
     public let events: AnyPublisher<AnyPublisher<CollectionItemEvent, Error>, Never>
diff --git a/ViewModels/Tests/ViewModelsTests/AddIdentityViewModelTests.swift b/ViewModels/Tests/ViewModelsTests/AddIdentityViewModelTests.swift
index 5c054f0..d096465 100644
--- a/ViewModels/Tests/ViewModelsTests/AddIdentityViewModelTests.swift
+++ b/ViewModels/Tests/ViewModelsTests/AddIdentityViewModelTests.swift
@@ -10,7 +10,7 @@ import ServiceLayerMocks
 @testable import ViewModels
 import XCTest
 
-class AddIdentityViewModelTests: XCTestCase {
+final class AddIdentityViewModelTests: XCTestCase {
     func testAddIdentity() throws {
         let uuid = UUID(uuidString: "E621E1F8-C36C-495A-93FC-0C247A3E6E5F")!
         let environment = AppEnvironment.mock(uuid: { uuid })
diff --git a/ViewModels/Tests/ViewModelsTests/RootViewModelTests.swift b/ViewModels/Tests/ViewModelsTests/RootViewModelTests.swift
index e2604e6..0dc2286 100644
--- a/ViewModels/Tests/ViewModelsTests/RootViewModelTests.swift
+++ b/ViewModels/Tests/ViewModelsTests/RootViewModelTests.swift
@@ -7,7 +7,7 @@ import ServiceLayerMocks
 @testable import ViewModels
 import XCTest
 
-class RootViewModelTests: XCTestCase {
+final class RootViewModelTests: XCTestCase {
     var cancellables = Set<AnyCancellable>()
 
     func testAddIdentity() throws {
diff --git a/Views/AccountHeaderView.swift b/Views/AccountHeaderView.swift
index 0f264c3..3e53e20 100644
--- a/Views/AccountHeaderView.swift
+++ b/Views/AccountHeaderView.swift
@@ -4,7 +4,7 @@ import Kingfisher
 import UIKit
 import ViewModels
 
-class AccountHeaderView: UIView {
+final class AccountHeaderView: UIView {
     let headerImageView = AnimatedImageView()
     let headerButton = UIButton()
     let noteTextView = TouchFallthroughTextView()
diff --git a/Views/AccountListCell.swift b/Views/AccountListCell.swift
index 84a5db5..cbf1b72 100644
--- a/Views/AccountListCell.swift
+++ b/Views/AccountListCell.swift
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class AccountListCell: UITableViewCell {
+final class AccountListCell: UITableViewCell {
     var viewModel: AccountViewModel?
 
     override func updateConfiguration(using state: UICellConfigurationState) {
diff --git a/Views/AccountView.swift b/Views/AccountView.swift
index f8ba210..1ef40a7 100644
--- a/Views/AccountView.swift
+++ b/Views/AccountView.swift
@@ -3,7 +3,7 @@
 import Kingfisher
 import UIKit
 
-class AccountView: UIView {
+final class AccountView: UIView {
     let avatarImageView = AnimatedImageView()
     let displayNameLabel = UILabel()
     let accountLabel = UILabel()
diff --git a/Views/ConversationListCell.swift b/Views/ConversationListCell.swift
index 73c1cbd..496cd95 100644
--- a/Views/ConversationListCell.swift
+++ b/Views/ConversationListCell.swift
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class ConversationListCell: UITableViewCell {
+final class ConversationListCell: UITableViewCell {
     var viewModel: ConversationViewModel?
 
     override func updateConfiguration(using state: UICellConfigurationState) {
diff --git a/Views/LoadMoreCell.swift b/Views/LoadMoreCell.swift
index ba97beb..3adceb6 100644
--- a/Views/LoadMoreCell.swift
+++ b/Views/LoadMoreCell.swift
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class LoadMoreCell: UITableViewCell {
+final class LoadMoreCell: UITableViewCell {
     var viewModel: LoadMoreViewModel?
 
     override func updateConfiguration(using state: UICellConfigurationState) {
diff --git a/Views/NotificationListCell.swift b/Views/NotificationListCell.swift
index 89c7149..dfb1caa 100644
--- a/Views/NotificationListCell.swift
+++ b/Views/NotificationListCell.swift
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class NotificationListCell: UITableViewCell {
+final class NotificationListCell: UITableViewCell {
     var viewModel: NotificationViewModel?
 
     override func updateConfiguration(using state: UICellConfigurationState) {
diff --git a/Views/PlayerView.swift b/Views/PlayerView.swift
index 3f144e7..f74cc48 100644
--- a/Views/PlayerView.swift
+++ b/Views/PlayerView.swift
@@ -3,7 +3,7 @@
 import AVKit
 import UIKit
 
-class PlayerView: UIView {
+final class PlayerView: UIView {
     override class var layerClass: AnyClass {
         AVPlayerLayer.self
     }
diff --git a/Views/PollOptionButton.swift b/Views/PollOptionButton.swift
index d1ef912..ebf317e 100644
--- a/Views/PollOptionButton.swift
+++ b/Views/PollOptionButton.swift
@@ -3,7 +3,7 @@
 import Mastodon
 import UIKit
 
-class PollOptionButton: UIButton {
+final class PollOptionButton: UIButton {
     init(title: String, emoji: [Emoji], multipleSelection: Bool) {
         super.init(frame: .zero)
 
diff --git a/Views/PollResultView.swift b/Views/PollResultView.swift
index d30d7c6..dab90bd 100644
--- a/Views/PollResultView.swift
+++ b/Views/PollResultView.swift
@@ -3,7 +3,7 @@
 import Mastodon
 import UIKit
 
-class PollResultView: UIView {
+final class PollResultView: UIView {
     private let verticalStackView = UIStackView()
     private let horizontalStackView = UIStackView()
     private let titleLabel = UILabel()
diff --git a/Views/Status/StatusListCell.swift b/Views/Status/StatusListCell.swift
index 01382a8..fd04c16 100644
--- a/Views/Status/StatusListCell.swift
+++ b/Views/Status/StatusListCell.swift
@@ -3,7 +3,7 @@
 import UIKit
 import ViewModels
 
-class StatusListCell: UITableViewCell {
+final class StatusListCell: UITableViewCell {
     var viewModel: StatusViewModel?
 
     override func updateConfiguration(using state: UICellConfigurationState) {
diff --git a/Views/WebfingerIndicatorView.swift b/Views/WebfingerIndicatorView.swift
index 5787f26..9bb9d9b 100644
--- a/Views/WebfingerIndicatorView.swift
+++ b/Views/WebfingerIndicatorView.swift
@@ -2,7 +2,7 @@
 
 import UIKit
 
-class WebfingerIndicatorView: UIVisualEffectView {
+final class WebfingerIndicatorView: UIVisualEffectView {
     private let activityIndicatorView = UIActivityIndicatorView()
 
     init() {