diff --git a/platforms/swift/Samples/CheckoutKitSwiftDemo/CheckoutKitSwiftDemo/Sources/Lib/Logger.swift b/platforms/swift/Samples/CheckoutKitSwiftDemo/CheckoutKitSwiftDemo/Sources/Lib/Logger.swift
index baf31052..6cb895e1 100644
--- a/platforms/swift/Samples/CheckoutKitSwiftDemo/CheckoutKitSwiftDemo/Sources/Lib/Logger.swift
+++ b/platforms/swift/Samples/CheckoutKitSwiftDemo/CheckoutKitSwiftDemo/Sources/Lib/Logger.swift
@@ -1,10 +1,10 @@
 import Foundation
 import ShopifyCheckoutKit
 
-class FileLogger: Logger {
-    private var fileHandle: FileHandle?
+final class FileLogger: Logger {
+    private let fileHandle: FileHandle?
 
-    var logFileUrl: URL
+    let logFileUrl: URL
 
     public init(_ filename: String) {
         let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
@@ -18,6 +18,7 @@ class FileLogger: Logger {
         do {
             fileHandle = try FileHandle(forWritingTo: logFileUrl)
         } catch let error as NSError {
+            fileHandle = nil
             print("Couldn't open the log file. Error: \(error)")
         }
     }
diff --git a/platforms/swift/Sources/ShopifyAcceleratedCheckouts/ShopifyAcceleratedCheckouts.swift b/platforms/swift/Sources/ShopifyAcceleratedCheckouts/ShopifyAcceleratedCheckouts.swift
index 15ccd698..da76fea0 100644
--- a/platforms/swift/Sources/ShopifyAcceleratedCheckouts/ShopifyAcceleratedCheckouts.swift
+++ b/platforms/swift/Sources/ShopifyAcceleratedCheckouts/ShopifyAcceleratedCheckouts.swift
@@ -8,13 +8,16 @@ public enum ShopifyAcceleratedCheckouts {
 
     /// The logging level for Accelerated Checkouts operations
     /// Default: .error - which will emit "error" and "fault" logs
-    public static var logLevel: LogLevel = .error {
-        didSet {
-            logger.logLevel = logLevel
+    public static var logLevel: LogLevel {
+        get {
+            logger.logLevel
+        }
+        set {
+            logger.logLevel = newValue
         }
     }
 
     /// Shared logger for ShopifyAcceleratedCheckouts
     /// To modify the logLevel
-    internal static var logger = OSLogger(prefix: name, logLevel: logLevel)
+    internal static let logger = OSLogger(prefix: name, logLevel: .error)
 }
diff --git a/platforms/swift/Sources/ShopifyCheckoutKit/Configuration.swift b/platforms/swift/Sources/ShopifyCheckoutKit/Configuration.swift
index ab0da97b..be8bcc53 100644
--- a/platforms/swift/Sources/ShopifyCheckoutKit/Configuration.swift
+++ b/platforms/swift/Sources/ShopifyCheckoutKit/Configuration.swift
@@ -1,6 +1,6 @@
 import UIKit
 
-public struct Platform: Equatable {
+public struct Platform: Equatable, Sendable {
     public let identifier: String
     public let version: String?
 
@@ -11,7 +11,7 @@ public struct Platform: Equatable {
     }
 }
 
-public struct Configuration {
+public struct Configuration: Sendable {
     /// Determines the color scheme used when checkout is presented.
     ///
     /// By default, the color scheme is determined based on the current
@@ -48,7 +48,7 @@ public struct Configuration {
 }
 
 extension Configuration {
-    public enum ColorScheme: String, CaseIterable {
+    public enum ColorScheme: String, CaseIterable, Sendable {
         /// Uses a light, idiomatic color scheme.
         case light
         /// Uses a dark, idiomatic color scheme.
@@ -61,7 +61,7 @@ extension Configuration {
 }
 
 extension Configuration {
-    public struct Confetti {
+    public struct Confetti: Sendable {
         public var enabled: Bool = false
 
         public var particles = [UIImage]()
diff --git a/platforms/swift/Sources/ShopifyCheckoutKit/LockedValue.swift b/platforms/swift/Sources/ShopifyCheckoutKit/LockedValue.swift
new file mode 100644
index 00000000..3a36e2c4
--- /dev/null
+++ b/platforms/swift/Sources/ShopifyCheckoutKit/LockedValue.swift
@@ -0,0 +1,100 @@
+import Foundation
+import os.lock
+
+private protocol LockedValueStorage<Value>: Sendable {
+    associatedtype Value: Sendable
+
+    func get() -> Value
+    func set(_ newValue: Value)
+    func update(_ block: (inout Value) -> Void)
+}
+
+@available(iOS 16.0, *)
+private final class OSAllocatedUnfairLockedValueStorage<Value: Sendable>: LockedValueStorage {
+    /// When the package minimum deployment target is iOS 18, consider
+    /// replacing this storage with Synchronization.Mutex<Value>.
+    private let lock: OSAllocatedUnfairLock<Value>
+
+    init(_ value: Value) {
+        lock = OSAllocatedUnfairLock(initialState: value)
+    }
+
+    func get() -> Value {
+        lock.withLock { $0 }
+    }
+
+    func set(_ newValue: Value) {
+        lock.withLock {
+            $0 = newValue
+        }
+    }
+
+    func update(_ block: (inout Value) -> Void) {
+        lock.withLockUnchecked {
+            block(&$0)
+        }
+    }
+}
+
+/// iOS 15 fallback for lock-backed Sendable storage.
+///
+/// SAFETY:
+/// - `value` is only read and written while holding `lock`.
+/// - `Value` is constrained to `Sendable`, so returned values can cross concurrency domains.
+/// - This exists because `OSAllocatedUnfairLock` is only available on iOS 16+.
+///
+/// Delete this fallback when the package minimum deployment target is iOS 16.
+@available(iOS, deprecated: 16.0, message: "Use OSAllocatedUnfairLockedValueStorage on iOS 16+.")
+private final class NSLockedValueStorage<Value: Sendable>: LockedValueStorage, @unchecked Sendable {
+    private let lock = NSLock()
+    private var value: Value
+
+    init(_ value: Value) {
+        self.value = value
+    }
+
+    func get() -> Value {
+        lock.withLock { value }
+    }
+
+    func set(_ newValue: Value) {
+        lock.withLock {
+            value = newValue
+        }
+    }
+
+    func update(_ block: (inout Value) -> Void) {
+        lock.withLock {
+            block(&value)
+        }
+    }
+}
+
+/// Lock-backed storage for mutable values that must remain synchronously readable and writable.
+///
+/// Use this for module-internal backing storage when a public or static mutable API needs to
+/// preserve synchronous mutation, but the stored value would otherwise be non-isolated shared
+/// mutable state under Swift 6 concurrency checking.
+final class LockedValue<Value: Sendable>: Sendable {
+    private let storage: any LockedValueStorage<Value>
+
+    init(_ value: Value) {
+        if #available(iOS 16.0, *) {
+            storage = OSAllocatedUnfairLockedValueStorage(value)
+        } else {
+            storage = NSLockedValueStorage(value)
+        }
+    }
+
+    func get() -> Value {
+        storage.get()
+    }
+
+    func set(_ newValue: Value) {
+        storage.set(newValue)
+    }
+
+    func update(_ block: (inout Value) -> Void) {
+        storage.update(block)
+    }
+}
diff --git a/platforms/swift/Sources/ShopifyCheckoutKit/Logger.swift b/platforms/swift/Sources/ShopifyCheckoutKit/Logger.swift
index 0ce01e2d..6081d9dd 100644
--- a/platforms/swift/Sources/ShopifyCheckoutKit/Logger.swift
+++ b/platforms/swift/Sources/ShopifyCheckoutKit/Logger.swift
@@ -3,28 +3,55 @@ import os.log
 
 private let subsystem = "com.shopify.checkoutkit"
 
-public enum LogLevel: String, CaseIterable {
+public enum LogLevel: String, CaseIterable, Sendable {
     case all
     case debug
     case error
     case none
 }
 
-public class OSLogger {
+public final class OSLogger: Sendable {
     private let logger = OSLog(subsystem: subsystem, category: OSLog.Category.pointsOfInterest)
-    private var prefix: String
-    package var logLevel: LogLevel
+    private let prefix: String
+    private let lockedLogLevel: LockedValue<LogLevel>
+    private let sendToOSLogHandler: (@Sendable (String, OSLogType) -> Void)?
 
-    public static var shared = OSLogger()
+    package var logLevel: LogLevel {
+        get {
+            lockedLogLevel.get()
+        }
+        set {
+            lockedLogLevel.set(newValue)
+        }
+    }
+
+    private static let lockedSharedLogger = LockedValue(OSLogger())
+
+    public static var shared: OSLogger {
+        get {
+            lockedSharedLogger.get()
+        }
+        set {
+            lockedSharedLogger.set(newValue)
+        }
+    }
+
+    public convenience init() {
+        self.init(prefix: "ShopifyCheckoutKit", logLevel: ShopifyCheckoutKit.configuration.logLevel)
+    }
 
-    public init() {
-        prefix = "ShopifyCheckoutKit"
-        logLevel = ShopifyCheckoutKit.configuration.logLevel
+    public convenience init(prefix: String, logLevel: LogLevel) {
+        self.init(prefix: prefix, logLevel: logLevel, sendToOSLogHandler: nil)
     }
 
-    public init(prefix: String, logLevel: LogLevel) {
+    init(
+        prefix: String,
+        logLevel: LogLevel,
+        sendToOSLogHandler: (@Sendable (String, OSLogType) -> Void)?
+    ) {
         self.prefix = prefix
-        self.logLevel = logLevel
+        lockedLogLevel = LockedValue(logLevel)
+        self.sendToOSLogHandler = sendToOSLogHandler
     }
 
     public func debug(_ message: String) {
@@ -54,24 +81,30 @@ public class OSLogger {
     /// Capturing `os_log` output is not possible
     /// This indirection lets us capture messages in `LoggerTests.swift`
     internal func sendToOSLog(_ message: String, type: OSLogType) {
-        os_log("%@", log: logger, type: type, message)
+        if let sendToOSLogHandler {
+            sendToOSLogHandler(message, type)
+        } else {
+            os_log("%@", log: logger, type: type, message)
+        }
     }
 
     private func shouldEmit(_ choice: LogLevel) -> Bool {
-        if logLevel == .none {
+        let currentLogLevel = logLevel
+
+        if currentLogLevel == .none {
             return false
         }
 
-        return logLevel == .all || logLevel == choice
+        return currentLogLevel == .all || currentLogLevel == choice
     }
 }
 
-public protocol Logger {
+public protocol Logger: Sendable {
     func log(_ message: String)
     func clearLogs()
 }
 
-public class NoOpLogger: Logger {
+public final class NoOpLogger: Logger {
     public func log(_: String) {}
 
     public func clearLogs() {}
diff --git a/platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift b/platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
index 5ee84e63..caae2187 100644
--- a/platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
+++ b/platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
@@ -6,16 +6,26 @@ import UIKit
 /// The version of the `ShopifyCheckoutKit` library.
 public let version = "4.0.0-alpha.1"
 
+private let lockedCheckoutKitConfiguration = LockedValue(Configuration())
+
 /// The configuration options for the `ShopifyCheckoutKit` library.
-public var configuration = Configuration() {
-    didSet {
-        OSLogger.shared.logLevel = configuration.logLevel
+public var configuration: Configuration {
+    get { lockedCheckoutKitConfiguration.get() }
+    set {
+        lockedCheckoutKitConfiguration.set(newValue)
+        applyConfigurationChange()
     }
 }
 
 /// A convienence function for configuring the `ShopifyCheckoutKit` library.
 public func configure(_ block: (inout Configuration) -> Void) {
-    block(&configuration)
+    lockedCheckoutKitConfiguration.update(block)
+    applyConfigurationChange()
+}
+
+private func applyConfigurationChange() {
+    let configuration = lockedCheckoutKitConfiguration.get()
+    OSLogger.shared.logLevel = configuration.logLevel
 }
 
 @MainActor
diff --git a/platforms/swift/Tests/ShopifyCheckoutKitTests/ConfigurationTests.swift b/platforms/swift/Tests/ShopifyCheckoutKitTests/ConfigurationTests.swift
index 1792170d..d0a6ec8f 100644
--- a/platforms/swift/Tests/ShopifyCheckoutKitTests/ConfigurationTests.swift
+++ b/platforms/swift/Tests/ShopifyCheckoutKitTests/ConfigurationTests.swift
@@ -5,7 +5,15 @@ import XCTest
 class ConfigurationTests: XCTestCase {
     override func setUp() {
         super.setUp()
-        // Reset configuration to defaults
+        resetConfigurationState()
+    }
+
+    override func tearDown() {
+        resetConfigurationState()
+        super.tearDown()
+    }
+
+    private func resetConfigurationState() {
         ShopifyCheckoutKit.configuration = Configuration()
     }
 
@@ -27,4 +35,27 @@ class ConfigurationTests: XCTestCase {
         ShopifyCheckoutKit.configuration.closeButtonTintColor = nil
         XCTAssertNil(ShopifyCheckoutKit.configuration.closeButtonTintColor)
     }
+
+    func testColorSchemeCanBeSetDirectly() {
+        ShopifyCheckoutKit.configuration.colorScheme = .light
+
+        XCTAssertEqual(ShopifyCheckoutKit.configuration.colorScheme, .light)
+    }
+
+    func testConfigureCanBatchConfigurationChanges() {
+        ShopifyCheckoutKit.configure {
+            $0.colorScheme = .dark
+            $0.closeButtonTintColor = .blue
+        }
+
+        XCTAssertEqual(ShopifyCheckoutKit.configuration.colorScheme, .dark)
+        XCTAssertEqual(ShopifyCheckoutKit.configuration.closeButtonTintColor, .blue)
+    }
+
+    func testDirectConfigurationMutationUpdatesLogger() {
+        ShopifyCheckoutKit.configuration.logLevel = .all
+
+        XCTAssertEqual(ShopifyCheckoutKit.configuration.logLevel, .all)
+        XCTAssertEqual(OSLogger.shared.logLevel, .all)
+    }
 }
diff --git a/platforms/swift/Tests/ShopifyCheckoutKitTests/LockedValueTests.swift b/platforms/swift/Tests/ShopifyCheckoutKitTests/LockedValueTests.swift
new file mode 100644
index 00000000..2e4e1577
--- /dev/null
+++ b/platforms/swift/Tests/ShopifyCheckoutKitTests/LockedValueTests.swift
@@ -0,0 +1,41 @@
+@testable import ShopifyCheckoutKit
+import XCTest
+
+final class LockedValueTests: XCTestCase {
+    func testGetReturnsInitialValue() {
+        let value = LockedValue("initial")
+
+        XCTAssertEqual(value.get(), "initial")
+    }
+
+    func testSetReplacesStoredValue() {
+        let value = LockedValue("initial")
+
+        value.set("updated")
+
+        XCTAssertEqual(value.get(), "updated")
+    }
+
+    func testUpdateMutatesStoredValue() {
+        let value = LockedValue(["initial"])
+
+        value.update { storedValue in
+            storedValue.append("updated")
+        }
+
+        XCTAssertEqual(value.get(), ["initial", "updated"])
+    }
+
+    func testUpdateSerializesConcurrentMutations() {
+        let value = LockedValue(0)
+        let iterations = 1000
+
+        DispatchQueue.concurrentPerform(iterations: iterations) { _ in
+            value.update { storedValue in
+                storedValue += 1
+            }
+        }
+
+        XCTAssertEqual(value.get(), iterations)
+    }
+}
diff --git a/platforms/swift/Tests/ShopifyCheckoutKitTests/LoggerTests.swift b/platforms/swift/Tests/ShopifyCheckoutKitTests/LoggerTests.swift
index fc0590cd..b4c22522 100644
--- a/platforms/swift/Tests/ShopifyCheckoutKitTests/LoggerTests.swift
+++ b/platforms/swift/Tests/ShopifyCheckoutKitTests/LoggerTests.swift
@@ -2,21 +2,44 @@ import os.log
 @testable import ShopifyCheckoutKit
 import XCTest
 
-class TestableOSLogger: OSLogger {
-    private(set) var capturedMessages: [(message: String, type: OSLogType)] = []
-    private let testPrefix: String
-    override init() {
-        testPrefix = "ShopifyCheckoutKit"
-        super.init()
+final class TestableOSLogger: Sendable {
+    private let capturedMessagesStorage = LockedValue([(message: String, type: OSLogType)]())
+    private let logger: OSLogger
+
+    var capturedMessages: [(message: String, type: OSLogType)] {
+        capturedMessagesStorage.get()
     }
 
-    override init(prefix: String, logLevel: LogLevel) {
-        testPrefix = prefix
-        super.init(prefix: prefix, logLevel: logLevel)
+    convenience init() {
+        self.init(prefix: "ShopifyCheckoutKit", logLevel: ShopifyCheckoutKit.configuration.logLevel)
     }
 
-    override func sendToOSLog(_ message: String, type: OSLogType) {
-        capturedMessages.append((message: message, type: type))
+    init(prefix: String, logLevel: LogLevel) {
+        logger = OSLogger(
+            prefix: prefix,
+            logLevel: logLevel,
+            sendToOSLogHandler: { [capturedMessagesStorage] message, type in
+                capturedMessagesStorage.update {
+                    $0.append((message: message, type: type))
+                }
+            }
+        )
+    }
+
+    func info(_ message: String) {
+        logger.info(message)
+    }
+
+    func debug(_ message: String) {
+        logger.debug(message)
+    }
+
+    func error(_ message: String) {
+        logger.error(message)
+    }
+
+    func fault(_ message: String) {
+        logger.fault(message)
     }
 }
 
@@ -37,9 +60,23 @@ final class OSLoggerTests: XCTestCase {
         XCTAssertNotNil(OSLogger.shared)
     }
 
-    func test_defaultInitializer_withNoParameters_shouldMaintainBackwardsCompatibility() {
+    func test_defaultInitializer_withNoParameters_shouldUseConfigurationLogLevel() {
+        ShopifyCheckoutKit.configure { $0.logLevel = .debug }
+
         let logger = OSLogger()
-        XCTAssertNotNil(logger)
+
+        XCTAssertEqual(logger.logLevel, .debug)
+    }
+
+    func test_sharedLogger_canBeReplaced() {
+        let originalLogger = OSLogger.shared
+        defer { OSLogger.shared = originalLogger }
+
+        let replacementLogger = OSLogger(prefix: "Replacement", logLevel: .debug)
+
+        OSLogger.shared = replacementLogger
+
+        XCTAssertTrue(OSLogger.shared === replacementLogger)
     }
 
     func test_logLevelNone_withAllLogCalls_shouldBlockAllLogging() {
diff --git a/platforms/swift/Tests/ShopifyCheckoutKitTests/Mocks/MockLogger.swift b/platforms/swift/Tests/ShopifyCheckoutKitTests/Mocks/MockLogger.swift
index d5a8ccf0..06ffaf45 100644
--- a/platforms/swift/Tests/ShopifyCheckoutKitTests/Mocks/MockLogger.swift
+++ b/platforms/swift/Tests/ShopifyCheckoutKitTests/Mocks/MockLogger.swift
@@ -1,11 +1,7 @@
 @testable import ShopifyCheckoutKit
 
-class MockLogger: NoOpLogger {
-    var loggedError: Error?
-    var loggedMessage: String?
+struct MockLogger: Logger {
+    func log(_: String) {}
 
-    func logError(_ error: Error, _ message: String) {
-        loggedError = error
-        loggedMessage = message
-    }
+    func clearLogs() {}
 }
diff --git a/platforms/swift/api/ShopifyAcceleratedCheckouts.json b/platforms/swift/api/ShopifyAcceleratedCheckouts.json
index 9bee51c1..d5daeb64 100644
--- a/platforms/swift/api/ShopifyAcceleratedCheckouts.json
+++ b/platforms/swift/api/ShopifyAcceleratedCheckouts.json
@@ -131,11 +131,6 @@
             "mangledName": "$s27ShopifyAcceleratedCheckoutsAAO8logLevel0A11CheckoutKit03LogE0OvpZ",
             "moduleName": "ShopifyAcceleratedCheckouts",
             "static": true,
-            "declAttributes": [
-              "HasInitialValue",
-              "HasStorage"
-            ],
-            "hasStorage": true,
             "accessors": [
               {
                 "kind": "Accessor",
@@ -154,7 +149,6 @@
                 "mangledName": "$s27ShopifyAcceleratedCheckoutsAAO8logLevel0A11CheckoutKit03LogE0OvgZ",
                 "moduleName": "ShopifyAcceleratedCheckouts",
                 "static": true,
-                "implicit": true,
                 "accessorKind": "get"
               },
               {
@@ -179,7 +173,6 @@
                 "mangledName": "$s27ShopifyAcceleratedCheckoutsAAO8logLevel0A11CheckoutKit03LogE0OvsZ",
                 "moduleName": "ShopifyAcceleratedCheckouts",
                 "static": true,
-                "implicit": true,
                 "accessorKind": "set"
               }
             ]
diff --git a/platforms/swift/api/ShopifyCheckoutKit.json b/platforms/swift/api/ShopifyCheckoutKit.json
index 49d87b3c..8ca66d23 100644
--- a/platforms/swift/api/ShopifyCheckoutKit.json
+++ b/platforms/swift/api/ShopifyCheckoutKit.json
@@ -95,6 +95,13 @@
         "declKind": "Import",
         "moduleName": "ShopifyCheckoutKit"
       },
+      {
+        "kind": "Import",
+        "name": "os.lock",
+        "printedName": "os.lock",
+        "declKind": "Import",
+        "moduleName": "ShopifyCheckoutKit"
+      },
       {
         "kind": "Import",
         "name": "os.log",
@@ -2631,6 +2638,20 @@
             "usr": "s:SQ",
             "mangledName": "$sSQ"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -3841,6 +3862,20 @@
                 "usr": "s:s12CaseIterableP",
                 "mangledName": "$ss12CaseIterableP"
               },
+              {
+                "kind": "Conformance",
+                "name": "Sendable",
+                "printedName": "Sendable",
+                "usr": "s:s8SendableP",
+                "mangledName": "$ss8SendableP"
+              },
+              {
+                "kind": "Conformance",
+                "name": "SendableMetatype",
+                "printedName": "SendableMetatype",
+                "usr": "s:s16SendableMetatypeP",
+                "mangledName": "$ss16SendableMetatypeP"
+              },
               {
                 "kind": "Conformance",
                 "name": "Copyable",
@@ -4039,6 +4074,20 @@
             "moduleName": "ShopifyCheckoutKit",
             "isFromExtension": true,
             "conformances": [
+              {
+                "kind": "Conformance",
+                "name": "Sendable",
+                "printedName": "Sendable",
+                "usr": "s:s8SendableP",
+                "mangledName": "$ss8SendableP"
+              },
+              {
+                "kind": "Conformance",
+                "name": "SendableMetatype",
+                "printedName": "SendableMetatype",
+                "usr": "s:s16SendableMetatypeP",
+                "mangledName": "$ss16SendableMetatypeP"
+              },
               {
                 "kind": "Conformance",
                 "name": "Copyable",
@@ -4061,6 +4110,20 @@
         "mangledName": "$s18ShopifyCheckoutKit13ConfigurationV",
         "moduleName": "ShopifyCheckoutKit",
         "conformances": [
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -4486,6 +4549,20 @@
             "usr": "s:s12CaseIterableP",
             "mangledName": "$ss12CaseIterableP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -4525,9 +4602,8 @@
             "moduleName": "ShopifyCheckoutKit",
             "isInternal": true,
             "declAttributes": [
-              "HasStorage"
+              "Final"
             ],
-            "hasStorage": true,
             "accessors": [
               {
                 "kind": "Accessor",
@@ -4545,10 +4621,9 @@
                 "usr": "s:18ShopifyCheckoutKit8OSLoggerC8logLevelAA03LogF0Ovg",
                 "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC8logLevelAA03LogF0Ovg",
                 "moduleName": "ShopifyCheckoutKit",
-                "implicit": true,
                 "isInternal": true,
                 "declAttributes": [
-                  "Transparent"
+                  "Final"
                 ],
                 "accessorKind": "get"
               },
@@ -4573,10 +4648,9 @@
                 "usr": "s:18ShopifyCheckoutKit8OSLoggerC8logLevelAA03LogF0Ovs",
                 "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC8logLevelAA03LogF0Ovs",
                 "moduleName": "ShopifyCheckoutKit",
-                "implicit": true,
                 "isInternal": true,
                 "declAttributes": [
-                  "Transparent"
+                  "Final"
                 ],
                 "accessorKind": "set"
               }
@@ -4600,11 +4674,8 @@
             "moduleName": "ShopifyCheckoutKit",
             "static": true,
             "declAttributes": [
-              "HasInitialValue",
-              "Final",
-              "HasStorage"
+              "Final"
             ],
-            "hasStorage": true,
             "accessors": [
               {
                 "kind": "Accessor",
@@ -4623,10 +4694,8 @@
                 "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC6sharedACvgZ",
                 "moduleName": "ShopifyCheckoutKit",
                 "static": true,
-                "implicit": true,
                 "declAttributes": [
-                  "Final",
-                  "Transparent"
+                  "Final"
                 ],
                 "accessorKind": "get"
               },
@@ -4652,10 +4721,8 @@
                 "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC6sharedACvsZ",
                 "moduleName": "ShopifyCheckoutKit",
                 "static": true,
-                "implicit": true,
                 "declAttributes": [
-                  "Final",
-                  "Transparent"
+                  "Final"
                 ],
                 "accessorKind": "set"
               }
@@ -4677,7 +4744,7 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerCACycfc",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerCACycfc",
             "moduleName": "ShopifyCheckoutKit",
-            "init_kind": "Designated"
+            "init_kind": "Convenience"
           },
           {
             "kind": "Constructor",
@@ -4707,7 +4774,7 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerC6prefix8logLevelACSS_AA03LogG0Otcfc",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC6prefix8logLevelACSS_AA03LogG0Otcfc",
             "moduleName": "ShopifyCheckoutKit",
-            "init_kind": "Designated"
+            "init_kind": "Convenience"
           },
           {
             "kind": "Function",
@@ -4730,6 +4797,9 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerC5debugyySSF",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC5debugyySSF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           },
           {
@@ -4753,6 +4823,9 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerC4infoyySSF",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC4infoyySSF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           },
           {
@@ -4776,6 +4849,9 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerC5erroryySSF",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC5erroryySSF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           },
           {
@@ -4799,6 +4875,9 @@
             "usr": "s:18ShopifyCheckoutKit8OSLoggerC5faultyySSF",
             "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC5faultyySSF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           }
         ],
@@ -4806,7 +4885,25 @@
         "usr": "s:18ShopifyCheckoutKit8OSLoggerC",
         "mangledName": "$s18ShopifyCheckoutKit8OSLoggerC",
         "moduleName": "ShopifyCheckoutKit",
+        "declAttributes": [
+          "Final"
+        ],
+        "hasMissingDesignatedInitializers": true,
         "conformances": [
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -4879,6 +4976,7 @@
         "usr": "s:18ShopifyCheckoutKit6LoggerP",
         "mangledName": "$s18ShopifyCheckoutKit6LoggerP",
         "moduleName": "ShopifyCheckoutKit",
+        "genericSig": "<Self : Swift.Sendable>",
         "conformances": [
           {
             "kind": "Conformance",
@@ -4893,6 +4991,20 @@
             "printedName": "Copyable",
             "usr": "s:s8CopyableP",
             "mangledName": "$ss8CopyableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
           }
         ]
       },
@@ -4922,6 +5034,9 @@
             "usr": "s:18ShopifyCheckoutKit10NoOpLoggerC3logyySSF",
             "mangledName": "$s18ShopifyCheckoutKit10NoOpLoggerC3logyySSF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           },
           {
@@ -4939,6 +5054,9 @@
             "usr": "s:18ShopifyCheckoutKit10NoOpLoggerC9clearLogsyyF",
             "mangledName": "$s18ShopifyCheckoutKit10NoOpLoggerC9clearLogsyyF",
             "moduleName": "ShopifyCheckoutKit",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           }
         ],
@@ -4946,6 +5064,9 @@
         "usr": "s:18ShopifyCheckoutKit10NoOpLoggerC",
         "mangledName": "$s18ShopifyCheckoutKit10NoOpLoggerC",
         "moduleName": "ShopifyCheckoutKit",
+        "declAttributes": [
+          "Final"
+        ],
         "hasMissingDesignatedInitializers": true,
         "conformances": [
           {
@@ -4955,6 +5076,20 @@
             "usr": "s:18ShopifyCheckoutKit6LoggerP",
             "mangledName": "$s18ShopifyCheckoutKit6LoggerP"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -5361,11 +5496,6 @@
         "usr": "s:18ShopifyCheckoutKit13configurationAA13ConfigurationVvp",
         "mangledName": "$s18ShopifyCheckoutKit13configurationAA13ConfigurationVvp",
         "moduleName": "ShopifyCheckoutKit",
-        "declAttributes": [
-          "HasInitialValue",
-          "HasStorage"
-        ],
-        "hasStorage": true,
         "accessors": [
           {
             "kind": "Accessor",
@@ -5383,7 +5513,6 @@
             "usr": "s:18ShopifyCheckoutKit13configurationAA13ConfigurationVvg",
             "mangledName": "$s18ShopifyCheckoutKit13configurationAA13ConfigurationVvg",
             "moduleName": "ShopifyCheckoutKit",
-            "implicit": true,
             "accessorKind": "get"
           },
           {
@@ -5407,7 +5536,6 @@
             "usr": "s:18ShopifyCheckoutKit13configurationAA13ConfigurationVvs",
             "mangledName": "$s18ShopifyCheckoutKit13configurationAA13ConfigurationVvs",
             "moduleName": "ShopifyCheckoutKit",
-            "implicit": true,
             "accessorKind": "set"
           }
         ]
diff --git a/platforms/swift/api/ShopifyCheckoutProtocol.json b/platforms/swift/api/ShopifyCheckoutProtocol.json
index 786e479b..f40a1f54 100644
--- a/platforms/swift/api/ShopifyCheckoutProtocol.json
+++ b/platforms/swift/api/ShopifyCheckoutProtocol.json
@@ -1341,6 +1341,96 @@
         "name": "Checkout",
         "printedName": "Checkout",
         "children": [
+          {
+            "kind": "Var",
+            "name": "attribution",
+            "printedName": "attribution",
+            "children": [
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]?",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Dictionary",
+                    "printedName": "[Swift.String : Swift.String]",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      }
+                    ],
+                    "usr": "s:SD"
+                  }
+                ],
+                "usr": "s:Sq"
+              }
+            ],
+            "declKind": "Var",
+            "usr": "s:23ShopifyCheckoutProtocol0B0V11attributionSDyS2SGSgvp",
+            "mangledName": "$s23ShopifyCheckoutProtocol0B0V11attributionSDyS2SGSgvp",
+            "moduleName": "ShopifyCheckoutProtocol",
+            "declAttributes": [
+              "HasStorage"
+            ],
+            "isLet": true,
+            "hasStorage": true,
+            "accessors": [
+              {
+                "kind": "Accessor",
+                "name": "Get",
+                "printedName": "Get()",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Optional",
+                    "printedName": "[Swift.String : Swift.String]?",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Dictionary",
+                        "printedName": "[Swift.String : Swift.String]",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          },
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          }
+                        ],
+                        "usr": "s:SD"
+                      }
+                    ],
+                    "usr": "s:Sq"
+                  }
+                ],
+                "declKind": "Accessor",
+                "usr": "s:23ShopifyCheckoutProtocol0B0V11attributionSDyS2SGSgvg",
+                "mangledName": "$s23ShopifyCheckoutProtocol0B0V11attributionSDyS2SGSgvg",
+                "moduleName": "ShopifyCheckoutProtocol",
+                "implicit": true,
+                "declAttributes": [
+                  "Transparent"
+                ],
+                "accessorKind": "get"
+              }
+            ]
+          },
           {
             "kind": "Var",
             "name": "buyer",
@@ -2352,6 +2442,43 @@
             "name": "CodingKeys",
             "printedName": "CodingKeys",
             "children": [
+              {
+                "kind": "Var",
+                "name": "attribution",
+                "printedName": "attribution",
+                "children": [
+                  {
+                    "kind": "TypeFunc",
+                    "name": "Function",
+                    "printedName": "(ShopifyCheckoutProtocol.Checkout.CodingKeys.Type) -> ShopifyCheckoutProtocol.Checkout.CodingKeys",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "CodingKeys",
+                        "printedName": "ShopifyCheckoutProtocol.Checkout.CodingKeys",
+                        "usr": "s:23ShopifyCheckoutProtocol0B0V10CodingKeysO"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Metatype",
+                        "printedName": "ShopifyCheckoutProtocol.Checkout.CodingKeys.Type",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "CodingKeys",
+                            "printedName": "ShopifyCheckoutProtocol.Checkout.CodingKeys",
+                            "usr": "s:23ShopifyCheckoutProtocol0B0V10CodingKeysO"
+                          }
+                        ]
+                      }
+                    ]
+                  }
+                ],
+                "declKind": "EnumElement",
+                "usr": "s:23ShopifyCheckoutProtocol0B0V10CodingKeysO11attributionyA2EmF",
+                "mangledName": "$s23ShopifyCheckoutProtocol0B0V10CodingKeysO11attributionyA2EmF",
+                "moduleName": "ShopifyCheckoutProtocol"
+              },
               {
                 "kind": "Var",
                 "name": "buyer",
@@ -3335,7 +3462,7 @@
           {
             "kind": "Constructor",
             "name": "init",
-            "printedName": "init(buyer:context:continueURL:currency:discounts:expiresAt:fulfillment:id:lineItems:links:messages:order:payment:signals:status:totals:ucp:)",
+            "printedName": "init(attribution:buyer:context:continueURL:currency:discounts:expiresAt:fulfillment:id:lineItems:links:messages:order:payment:signals:status:totals:ucp:)",
             "children": [
               {
                 "kind": "TypeNominal",
@@ -3343,6 +3470,34 @@
                 "printedName": "ShopifyCheckoutProtocol.Checkout",
                 "usr": "s:23ShopifyCheckoutProtocol0B0V"
               },
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]?",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Dictionary",
+                    "printedName": "[Swift.String : Swift.String]",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      }
+                    ],
+                    "usr": "s:SD"
+                  }
+                ],
+                "usr": "s:Sq"
+              },
               {
                 "kind": "TypeNominal",
                 "name": "Optional",
@@ -3559,8 +3714,8 @@
               }
             ],
             "declKind": "Constructor",
-            "usr": "s:23ShopifyCheckoutProtocol0B0V5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpAcA5BuyerVSg_AA7ContextVSgSSSgSSAA0B9DiscountsVSg10Foundation4DateVSgAA0B11FulfillmentVSgSSSayAA8LineItemVGSayAA4LinkVGSayAA7MessageVGSgAA17OrderConfirmationVSgAA7PaymentVSgAA7SignalsVSgAA0B6StatusOSayAA0B5TotalVGAA25UCPCheckoutResponseSchemaVtcfc",
-            "mangledName": "$s23ShopifyCheckoutProtocol0B0V5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpAcA5BuyerVSg_AA7ContextVSgSSSgSSAA0B9DiscountsVSg10Foundation4DateVSgAA0B11FulfillmentVSgSSSayAA8LineItemVGSayAA4LinkVGSayAA7MessageVGSgAA17OrderConfirmationVSgAA7PaymentVSgAA7SignalsVSgAA0B6StatusOSayAA0B5TotalVGAA25UCPCheckoutResponseSchemaVtcfc",
+            "usr": "s:23ShopifyCheckoutProtocol0B0V11attribution5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpACSDyS2SGSg_AA5BuyerVSgAA7ContextVSgSSSgSSAA0B9DiscountsVSg10Foundation4DateVSgAA0B11FulfillmentVSgSSSayAA8LineItemVGSayAA4LinkVGSayAA7MessageVGSgAA17OrderConfirmationVSgAA7PaymentVSgAA7SignalsVSgAA0B6StatusOSayAA0B5TotalVGAA25UCPCheckoutResponseSchemaVtcfc",
+            "mangledName": "$s23ShopifyCheckoutProtocol0B0V11attribution5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpACSDyS2SGSg_AA5BuyerVSgAA7ContextVSgSSSgSSAA0B9DiscountsVSg10Foundation4DateVSgAA0B11FulfillmentVSgSSSayAA8LineItemVGSayAA4LinkVGSayAA7MessageVGSgAA17OrderConfirmationVSgAA7PaymentVSgAA7SignalsVSgAA0B6StatusOSayAA0B5TotalVGAA25UCPCheckoutResponseSchemaVtcfc",
             "moduleName": "ShopifyCheckoutProtocol",
             "init_kind": "Designated"
           },
@@ -3703,7 +3858,7 @@
           {
             "kind": "Function",
             "name": "with",
-            "printedName": "with(buyer:context:continueURL:currency:discounts:expiresAt:fulfillment:id:lineItems:links:messages:order:payment:signals:status:totals:ucp:)",
+            "printedName": "with(attribution:buyer:context:continueURL:currency:discounts:expiresAt:fulfillment:id:lineItems:links:messages:order:payment:signals:status:totals:ucp:)",
             "children": [
               {
                 "kind": "TypeNominal",
@@ -3711,6 +3866,43 @@
                 "printedName": "ShopifyCheckoutProtocol.Checkout",
                 "usr": "s:23ShopifyCheckoutProtocol0B0V"
               },
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]??",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Optional",
+                    "printedName": "[Swift.String : Swift.String]?",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Dictionary",
+                        "printedName": "[Swift.String : Swift.String]",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          },
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          }
+                        ],
+                        "usr": "s:SD"
+                      }
+                    ],
+                    "usr": "s:Sq"
+                  }
+                ],
+                "hasDefaultArg": true,
+                "usr": "s:Sq"
+              },
               {
                 "kind": "TypeNominal",
                 "name": "Optional",
@@ -4080,8 +4272,8 @@
               }
             ],
             "declKind": "Func",
-            "usr": "s:23ShopifyCheckoutProtocol0B0V4with5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpAcA5BuyerVSgSg_AA7ContextVSgSgSSSgSgA2_AA0B9DiscountsVSgSg10Foundation4DateVSgSgAA0B11FulfillmentVSgSgA2_SayAA8LineItemVGSgSayAA4LinkVGSgSayAA7MessageVGSgSgAA17OrderConfirmationVSgSgAA7PaymentVSgSgAA7SignalsVSgSgAA0B6StatusOSgSayAA0B5TotalVGSgAA25UCPCheckoutResponseSchemaVSgtF",
-            "mangledName": "$s23ShopifyCheckoutProtocol0B0V4with5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpAcA5BuyerVSgSg_AA7ContextVSgSgSSSgSgA2_AA0B9DiscountsVSgSg10Foundation4DateVSgSgAA0B11FulfillmentVSgSgA2_SayAA8LineItemVGSgSayAA4LinkVGSgSayAA7MessageVGSgSgAA17OrderConfirmationVSgSgAA7PaymentVSgSgAA7SignalsVSgSgAA0B6StatusOSgSayAA0B5TotalVGSgAA25UCPCheckoutResponseSchemaVSgtF",
+            "usr": "s:23ShopifyCheckoutProtocol0B0V4with11attribution5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpACSDyS2SGSgSg_AA5BuyerVSgSgAA7ContextVSgSgSSSgSgA6_AA0B9DiscountsVSgSg10Foundation4DateVSgSgAA0B11FulfillmentVSgSgA6_SayAA8LineItemVGSgSayAA4LinkVGSgSayAA7MessageVGSgSgAA17OrderConfirmationVSgSgAA7PaymentVSgSgAA7SignalsVSgSgAA0B6StatusOSgSayAA0B5TotalVGSgAA25UCPCheckoutResponseSchemaVSgtF",
+            "mangledName": "$s23ShopifyCheckoutProtocol0B0V4with11attribution5buyer7context11continueURL8currency9discounts9expiresAt11fulfillment2id9lineItems5links8messages5order7payment7signals6status6totals3ucpACSDyS2SGSgSg_AA5BuyerVSgSgAA7ContextVSgSgSSSgSgA6_AA0B9DiscountsVSgSg10Foundation4DateVSgSgAA0B11FulfillmentVSgSgA6_SayAA8LineItemVGSgSayAA4LinkVGSgSayAA7MessageVGSgSgAA17OrderConfirmationVSgSgAA7PaymentVSgSgAA7SignalsVSgSgAA0B6StatusOSgSayAA0B5TotalVGSgAA25UCPCheckoutResponseSchemaVSgtF",
             "moduleName": "ShopifyCheckoutProtocol",
             "isFromExtension": true,
             "funcSelfKind": "NonMutating"
@@ -40603,6 +40795,96 @@
               }
             ]
           },
+          {
+            "kind": "Var",
+            "name": "attribution",
+            "printedName": "attribution",
+            "children": [
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]?",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Dictionary",
+                    "printedName": "[Swift.String : Swift.String]",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      }
+                    ],
+                    "usr": "s:SD"
+                  }
+                ],
+                "usr": "s:Sq"
+              }
+            ],
+            "declKind": "Var",
+            "usr": "s:23ShopifyCheckoutProtocol5OrderV11attributionSDyS2SGSgvp",
+            "mangledName": "$s23ShopifyCheckoutProtocol5OrderV11attributionSDyS2SGSgvp",
+            "moduleName": "ShopifyCheckoutProtocol",
+            "declAttributes": [
+              "HasStorage"
+            ],
+            "isLet": true,
+            "hasStorage": true,
+            "accessors": [
+              {
+                "kind": "Accessor",
+                "name": "Get",
+                "printedName": "Get()",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Optional",
+                    "printedName": "[Swift.String : Swift.String]?",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Dictionary",
+                        "printedName": "[Swift.String : Swift.String]",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          },
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          }
+                        ],
+                        "usr": "s:SD"
+                      }
+                    ],
+                    "usr": "s:Sq"
+                  }
+                ],
+                "declKind": "Accessor",
+                "usr": "s:23ShopifyCheckoutProtocol5OrderV11attributionSDyS2SGSgvg",
+                "mangledName": "$s23ShopifyCheckoutProtocol5OrderV11attributionSDyS2SGSgvg",
+                "moduleName": "ShopifyCheckoutProtocol",
+                "implicit": true,
+                "declAttributes": [
+                  "Transparent"
+                ],
+                "accessorKind": "get"
+              }
+            ]
+          },
           {
             "kind": "Var",
             "name": "checkoutID",
@@ -41185,6 +41467,43 @@
                 "mangledName": "$s23ShopifyCheckoutProtocol5OrderV10CodingKeysO11adjustmentsyA2EmF",
                 "moduleName": "ShopifyCheckoutProtocol"
               },
+              {
+                "kind": "Var",
+                "name": "attribution",
+                "printedName": "attribution",
+                "children": [
+                  {
+                    "kind": "TypeFunc",
+                    "name": "Function",
+                    "printedName": "(ShopifyCheckoutProtocol.Order.CodingKeys.Type) -> ShopifyCheckoutProtocol.Order.CodingKeys",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "CodingKeys",
+                        "printedName": "ShopifyCheckoutProtocol.Order.CodingKeys",
+                        "usr": "s:23ShopifyCheckoutProtocol5OrderV10CodingKeysO"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Metatype",
+                        "printedName": "ShopifyCheckoutProtocol.Order.CodingKeys.Type",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "CodingKeys",
+                            "printedName": "ShopifyCheckoutProtocol.Order.CodingKeys",
+                            "usr": "s:23ShopifyCheckoutProtocol5OrderV10CodingKeysO"
+                          }
+                        ]
+                      }
+                    ]
+                  }
+                ],
+                "declKind": "EnumElement",
+                "usr": "s:23ShopifyCheckoutProtocol5OrderV10CodingKeysO11attributionyA2EmF",
+                "mangledName": "$s23ShopifyCheckoutProtocol5OrderV10CodingKeysO11attributionyA2EmF",
+                "moduleName": "ShopifyCheckoutProtocol"
+              },
               {
                 "kind": "Var",
                 "name": "checkoutID",
@@ -41909,7 +42228,7 @@
           {
             "kind": "Constructor",
             "name": "init",
-            "printedName": "init(adjustments:checkoutID:currency:fulfillment:id:label:lineItems:messages:permalinkURL:totals:ucp:)",
+            "printedName": "init(adjustments:attribution:checkoutID:currency:fulfillment:id:label:lineItems:messages:permalinkURL:totals:ucp:)",
             "children": [
               {
                 "kind": "TypeNominal",
@@ -41939,6 +42258,34 @@
                 ],
                 "usr": "s:Sq"
               },
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]?",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Dictionary",
+                    "printedName": "[Swift.String : Swift.String]",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      },
+                      {
+                        "kind": "TypeNominal",
+                        "name": "String",
+                        "printedName": "Swift.String",
+                        "usr": "s:SS"
+                      }
+                    ],
+                    "usr": "s:SD"
+                  }
+                ],
+                "usr": "s:Sq"
+              },
               {
                 "kind": "TypeNominal",
                 "name": "String",
@@ -42041,8 +42388,8 @@
               }
             ],
             "declKind": "Constructor",
-            "usr": "s:23ShopifyCheckoutProtocol5OrderV11adjustments10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSg_S2SAA11FulfillmentVS2SSgSayAA0D8LineItemVGSayAA7MessageVGSgSSSayAA0B5TotalVGAA22UCPOrderResponseSchemaVtcfc",
-            "mangledName": "$s23ShopifyCheckoutProtocol5OrderV11adjustments10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSg_S2SAA11FulfillmentVS2SSgSayAA0D8LineItemVGSayAA7MessageVGSgSSSayAA0B5TotalVGAA22UCPOrderResponseSchemaVtcfc",
+            "usr": "s:23ShopifyCheckoutProtocol5OrderV11adjustments11attribution10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSg_SDyS2SGSgS2SAA11FulfillmentVS2SSgSayAA0D8LineItemVGSayAA7MessageVGSgSSSayAA0B5TotalVGAA22UCPOrderResponseSchemaVtcfc",
+            "mangledName": "$s23ShopifyCheckoutProtocol5OrderV11adjustments11attribution10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSg_SDyS2SGSgS2SAA11FulfillmentVS2SSgSayAA0D8LineItemVGSayAA7MessageVGSgSSSayAA0B5TotalVGAA22UCPOrderResponseSchemaVtcfc",
             "moduleName": "ShopifyCheckoutProtocol",
             "init_kind": "Designated"
           },
@@ -42185,7 +42532,7 @@
           {
             "kind": "Function",
             "name": "with",
-            "printedName": "with(adjustments:checkoutID:currency:fulfillment:id:label:lineItems:messages:permalinkURL:totals:ucp:)",
+            "printedName": "with(adjustments:attribution:checkoutID:currency:fulfillment:id:label:lineItems:messages:permalinkURL:totals:ucp:)",
             "children": [
               {
                 "kind": "TypeNominal",
@@ -42224,6 +42571,43 @@
                 "hasDefaultArg": true,
                 "usr": "s:Sq"
               },
+              {
+                "kind": "TypeNominal",
+                "name": "Optional",
+                "printedName": "[Swift.String : Swift.String]??",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Optional",
+                    "printedName": "[Swift.String : Swift.String]?",
+                    "children": [
+                      {
+                        "kind": "TypeNominal",
+                        "name": "Dictionary",
+                        "printedName": "[Swift.String : Swift.String]",
+                        "children": [
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          },
+                          {
+                            "kind": "TypeNominal",
+                            "name": "String",
+                            "printedName": "Swift.String",
+                            "usr": "s:SS"
+                          }
+                        ],
+                        "usr": "s:SD"
+                      }
+                    ],
+                    "usr": "s:Sq"
+                  }
+                ],
+                "hasDefaultArg": true,
+                "usr": "s:Sq"
+              },
               {
                 "kind": "TypeNominal",
                 "name": "Optional",
@@ -42416,8 +42800,8 @@
               }
             ],
             "declKind": "Func",
-            "usr": "s:23ShopifyCheckoutProtocol5OrderV4with11adjustments10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSgSg_SSSgAuA11FulfillmentVSgA2USgSayAA0D8LineItemVGSgSayAA7MessageVGSgSgAUSayAA0B5TotalVGSgAA22UCPOrderResponseSchemaVSgtF",
-            "mangledName": "$s23ShopifyCheckoutProtocol5OrderV4with11adjustments10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSgSg_SSSgAuA11FulfillmentVSgA2USgSayAA0D8LineItemVGSgSayAA7MessageVGSgSgAUSayAA0B5TotalVGSgAA22UCPOrderResponseSchemaVSgtF",
+            "usr": "s:23ShopifyCheckoutProtocol5OrderV4with11adjustments11attribution10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSgSg_SDyS2SGSgSgSSSgAyA11FulfillmentVSgA2YSgSayAA0D8LineItemVGSgSayAA7MessageVGSgSgAYSayAA0B5TotalVGSgAA22UCPOrderResponseSchemaVSgtF",
+            "mangledName": "$s23ShopifyCheckoutProtocol5OrderV4with11adjustments11attribution10checkoutID8currency11fulfillment2id5label9lineItems8messages12permalinkURL6totals3ucpACSayAA10AdjustmentVGSgSg_SDyS2SGSgSgSSSgAyA11FulfillmentVSgA2YSgSayAA0D8LineItemVGSgSayAA7MessageVGSgSgAYSayAA0B5TotalVGSgAA22UCPOrderResponseSchemaVSgtF",
             "moduleName": "ShopifyCheckoutProtocol",
             "isFromExtension": true,
             "funcSelfKind": "NonMutating"
@@ -66404,43 +66788,6 @@
             ],
             "funcSelfKind": "NonMutating"
           },
-          {
-            "kind": "Var",
-            "name": "hashValue",
-            "printedName": "hashValue",
-            "children": [
-              {
-                "kind": "TypeNominal",
-                "name": "Int",
-                "printedName": "Swift.Int",
-                "usr": "s:Si"
-              }
-            ],
-            "declKind": "Var",
-            "usr": "s:23ShopifyCheckoutProtocol8JSONNullC9hashValueSivp",
-            "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC9hashValueSivp",
-            "moduleName": "ShopifyCheckoutProtocol",
-            "accessors": [
-              {
-                "kind": "Accessor",
-                "name": "Get",
-                "printedName": "Get()",
-                "children": [
-                  {
-                    "kind": "TypeNominal",
-                    "name": "Int",
-                    "printedName": "Swift.Int",
-                    "usr": "s:Si"
-                  }
-                ],
-                "declKind": "Accessor",
-                "usr": "s:23ShopifyCheckoutProtocol8JSONNullC9hashValueSivg",
-                "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC9hashValueSivg",
-                "moduleName": "ShopifyCheckoutProtocol",
-                "accessorKind": "get"
-              }
-            ]
-          },
           {
             "kind": "Function",
             "name": "hash",
@@ -66463,6 +66810,9 @@
             "usr": "s:23ShopifyCheckoutProtocol8JSONNullC4hash4intoys6HasherVz_tF",
             "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC4hash4intoys6HasherVz_tF",
             "moduleName": "ShopifyCheckoutProtocol",
+            "declAttributes": [
+              "Final"
+            ],
             "funcSelfKind": "NonMutating"
           },
           {
@@ -66532,14 +66882,65 @@
             "usr": "s:23ShopifyCheckoutProtocol8JSONNullC6encode2toys7Encoder_p_tKF",
             "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC6encode2toys7Encoder_p_tKF",
             "moduleName": "ShopifyCheckoutProtocol",
+            "declAttributes": [
+              "Final"
+            ],
             "throwing": true,
             "funcSelfKind": "NonMutating"
+          },
+          {
+            "kind": "Var",
+            "name": "hashValue",
+            "printedName": "hashValue",
+            "children": [
+              {
+                "kind": "TypeNominal",
+                "name": "Int",
+                "printedName": "Swift.Int",
+                "usr": "s:Si"
+              }
+            ],
+            "declKind": "Var",
+            "usr": "s:23ShopifyCheckoutProtocol8JSONNullC9hashValueSivp",
+            "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC9hashValueSivp",
+            "moduleName": "ShopifyCheckoutProtocol",
+            "implicit": true,
+            "declAttributes": [
+              "Final"
+            ],
+            "accessors": [
+              {
+                "kind": "Accessor",
+                "name": "Get",
+                "printedName": "Get()",
+                "children": [
+                  {
+                    "kind": "TypeNominal",
+                    "name": "Int",
+                    "printedName": "Swift.Int",
+                    "usr": "s:Si"
+                  }
+                ],
+                "declKind": "Accessor",
+                "usr": "s:23ShopifyCheckoutProtocol8JSONNullC9hashValueSivg",
+                "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC9hashValueSivg",
+                "moduleName": "ShopifyCheckoutProtocol",
+                "implicit": true,
+                "declAttributes": [
+                  "Final"
+                ],
+                "accessorKind": "get"
+              }
+            ]
           }
         ],
         "declKind": "Class",
         "usr": "s:23ShopifyCheckoutProtocol8JSONNullC",
         "mangledName": "$s23ShopifyCheckoutProtocol8JSONNullC",
         "moduleName": "ShopifyCheckoutProtocol",
+        "declAttributes": [
+          "Final"
+        ],
         "conformances": [
           {
             "kind": "Conformance",
@@ -66562,6 +66963,13 @@
             "usr": "s:SH",
             "mangledName": "$sSH"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
           {
             "kind": "Conformance",
             "name": "Equatable",
@@ -66569,6 +66977,13 @@
             "usr": "s:SQ",
             "mangledName": "$sSQ"
           },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
@@ -66606,11 +67021,8 @@
             "mangledName": "$s23ShopifyCheckoutProtocol7JSONAnyC5valueypvp",
             "moduleName": "ShopifyCheckoutProtocol",
             "declAttributes": [
-              "Final",
-              "HasStorage"
+              "Final"
             ],
-            "isLet": true,
-            "hasStorage": true,
             "accessors": [
               {
                 "kind": "Accessor",
@@ -66627,10 +67039,8 @@
                 "usr": "s:23ShopifyCheckoutProtocol7JSONAnyC5valueypvg",
                 "mangledName": "$s23ShopifyCheckoutProtocol7JSONAnyC5valueypvg",
                 "moduleName": "ShopifyCheckoutProtocol",
-                "implicit": true,
                 "declAttributes": [
-                  "Final",
-                  "Transparent"
+                  "Final"
                 ],
                 "accessorKind": "get"
               }
@@ -66685,6 +67095,9 @@
             "usr": "s:23ShopifyCheckoutProtocol7JSONAnyC6encode2toys7Encoder_p_tKF",
             "mangledName": "$s23ShopifyCheckoutProtocol7JSONAnyC6encode2toys7Encoder_p_tKF",
             "moduleName": "ShopifyCheckoutProtocol",
+            "declAttributes": [
+              "Final"
+            ],
             "throwing": true,
             "funcSelfKind": "NonMutating"
           }
@@ -66693,6 +67106,9 @@
         "usr": "s:23ShopifyCheckoutProtocol7JSONAnyC",
         "mangledName": "$s23ShopifyCheckoutProtocol7JSONAnyC",
         "moduleName": "ShopifyCheckoutProtocol",
+        "declAttributes": [
+          "Final"
+        ],
         "conformances": [
           {
             "kind": "Conformance",
@@ -66708,6 +67124,20 @@
             "usr": "s:SE",
             "mangledName": "$sSE"
           },
+          {
+            "kind": "Conformance",
+            "name": "Sendable",
+            "printedName": "Sendable",
+            "usr": "s:s8SendableP",
+            "mangledName": "$ss8SendableP"
+          },
+          {
+            "kind": "Conformance",
+            "name": "SendableMetatype",
+            "printedName": "SendableMetatype",
+            "usr": "s:s16SendableMetatypeP",
+            "mangledName": "$ss16SendableMetatypeP"
+          },
           {
             "kind": "Conformance",
             "name": "Copyable",
diff --git a/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/Generated/Models.swift b/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/Generated/Models.swift
index e9b0269c..725e85a3 100644
--- a/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/Generated/Models.swift
+++ b/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/Generated/Models.swift
@@ -12,6 +12,7 @@ import Foundation
 /// Base checkout schema. Extensions compose onto this using allOf.
 // MARK: - Checkout
 public struct Checkout: Codable, Sendable {
+    public let attribution: [String: String]?
     /// Representation of the buyer.
     public let buyer: Buyer?
     public let context: Context?
@@ -47,7 +48,7 @@ public struct Checkout: Codable, Sendable {
     public let ucp: UCPCheckoutResponseSchema
 
     public enum CodingKeys: String, CodingKey {
-        case buyer, context
+        case attribution, buyer, context
         case continueURL = "continue_url"
         case currency, discounts
         case expiresAt = "expires_at"
@@ -56,7 +57,8 @@ public struct Checkout: Codable, Sendable {
         case links, messages, order, payment, signals, status, totals, ucp
     }
 
-    public init(buyer: Buyer?, context: Context?, continueURL: String?, currency: String, discounts: CheckoutDiscounts?, expiresAt: Date?, fulfillment: CheckoutFulfillment?, id: String, lineItems: [LineItem], links: [Link], messages: [Message]?, order: OrderConfirmation?, payment: Payment?, signals: Signals?, status: CheckoutStatus, totals: [CheckoutTotal], ucp: UCPCheckoutResponseSchema) {
+    public init(attribution: [String: String]?, buyer: Buyer?, context: Context?, continueURL: String?, currency: String, discounts: CheckoutDiscounts?, expiresAt: Date?, fulfillment: CheckoutFulfillment?, id: String, lineItems: [LineItem], links: [Link], messages: [Message]?, order: OrderConfirmation?, payment: Payment?, signals: Signals?, status: CheckoutStatus, totals: [CheckoutTotal], ucp: UCPCheckoutResponseSchema) {
+        self.attribution = attribution
         self.buyer = buyer
         self.context = context
         self.continueURL = continueURL
@@ -96,6 +98,7 @@ public extension Checkout {
     }
 
     func with(
+        attribution: [String: String]?? = nil,
         buyer: Buyer?? = nil,
         context: Context?? = nil,
         continueURL: String?? = nil,
@@ -115,6 +118,7 @@ public extension Checkout {
         ucp: UCPCheckoutResponseSchema? = nil
     ) -> Checkout {
         return Checkout(
+            attribution: attribution ?? self.attribution,
             buyer: buyer ?? self.buyer,
             context: context ?? self.context,
             continueURL: continueURL ?? self.continueURL,
@@ -1387,10 +1391,6 @@ public extension Link {
 /// Container for error, warning, or info messages.
 // MARK: - Message
 public struct Message: Codable, Sendable {
-    /// Warning code. Machine-readable identifier for the warning type (e.g., final_sale, prop65,
-    /// fulfillment_changed, age_restricted, etc.).
-    ///
-    /// Info code for programmatic handling.
     public let code: String?
     /// Human-readable message.
     ///
@@ -2447,6 +2447,9 @@ public struct Order: Codable, Sendable {
     /// Post-order events (refunds, returns, credits, disputes, cancellations, etc.) that exist
     /// independently of fulfillment.
     public let adjustments: [Adjustment]?
+    /// Snapshot of the attribution associated with the originating checkout. Read-only on the
+    /// order.
+    public let attribution: [String: String]?
     /// Associated checkout ID for reconciliation.
     public let checkoutID: String
     /// ISO 4217 currency code. MUST match the currency from the originating checkout session.
@@ -2469,7 +2472,7 @@ public struct Order: Codable, Sendable {
     public let ucp: UCPOrderResponseSchema
 
     public enum CodingKeys: String, CodingKey {
-        case adjustments
+        case adjustments, attribution
         case checkoutID = "checkout_id"
         case currency, fulfillment, id, label
         case lineItems = "line_items"
@@ -2478,8 +2481,9 @@ public struct Order: Codable, Sendable {
         case totals, ucp
     }
 
-    public init(adjustments: [Adjustment]?, checkoutID: String, currency: String, fulfillment: Fulfillment, id: String, label: String?, lineItems: [OrderLineItem], messages: [Message]?, permalinkURL: String, totals: [CheckoutTotal], ucp: UCPOrderResponseSchema) {
+    public init(adjustments: [Adjustment]?, attribution: [String: String]?, checkoutID: String, currency: String, fulfillment: Fulfillment, id: String, label: String?, lineItems: [OrderLineItem], messages: [Message]?, permalinkURL: String, totals: [CheckoutTotal], ucp: UCPOrderResponseSchema) {
         self.adjustments = adjustments
+        self.attribution = attribution
         self.checkoutID = checkoutID
         self.currency = currency
         self.fulfillment = fulfillment
@@ -2513,6 +2517,7 @@ public extension Order {
 
     func with(
         adjustments: [Adjustment]?? = nil,
+        attribution: [String: String]?? = nil,
         checkoutID: String? = nil,
         currency: String? = nil,
         fulfillment: Fulfillment? = nil,
@@ -2526,6 +2531,7 @@ public extension Order {
     ) -> Order {
         return Order(
             adjustments: adjustments ?? self.adjustments,
+            attribution: attribution ?? self.attribution,
             checkoutID: checkoutID ?? self.checkoutID,
             currency: currency ?? self.currency,
             fulfillment: fulfillment ?? self.fulfillment,
@@ -4143,247 +4149,5 @@ func newJSONEncoder() -> JSONEncoder {
 }
 
 // MARK: - Encode/decode helpers
-
-public class JSONNull: Codable, Hashable {
-
-    public static func == (lhs: JSONNull, rhs: JSONNull) -> Bool {
-            return true
-    }
-
-    public var hashValue: Int {
-            return 0
-    }
-
-    public func hash(into hasher: inout Hasher) {
-            // No-op
-    }
-
-    public init() {}
-
-    public required init(from decoder: Decoder) throws {
-            let container = try decoder.singleValueContainer()
-            if !container.decodeNil() {
-                    throw DecodingError.typeMismatch(JSONNull.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for JSONNull"))
-            }
-    }
-
-    public func encode(to encoder: Encoder) throws {
-            var container = encoder.singleValueContainer()
-            try container.encodeNil()
-    }
-}
-
-class JSONCodingKey: CodingKey {
-    let key: String
-
-    required init?(intValue: Int) {
-            return nil
-    }
-
-    required init?(stringValue: String) {
-            key = stringValue
-    }
-
-    var intValue: Int? {
-            return nil
-    }
-
-    var stringValue: String {
-            return key
-    }
-}
-
-public class JSONAny: Codable {
-
-    public let value: Any
-
-    static func decodingError(forCodingPath codingPath: [CodingKey]) -> DecodingError {
-            let context = DecodingError.Context(codingPath: codingPath, debugDescription: "Cannot decode JSONAny")
-            return DecodingError.typeMismatch(JSONAny.self, context)
-    }
-
-    static func encodingError(forValue value: Any, codingPath: [CodingKey]) -> EncodingError {
-            let context = EncodingError.Context(codingPath: codingPath, debugDescription: "Cannot encode JSONAny")
-            return EncodingError.invalidValue(value, context)
-    }
-
-    static func decode(from container: SingleValueDecodingContainer) throws -> Any {
-            if let value = try? container.decode(Bool.self) {
-                    return value
-            }
-            if let value = try? container.decode(Int64.self) {
-                    return value
-            }
-            if let value = try? container.decode(Double.self) {
-                    return value
-            }
-            if let value = try? container.decode(String.self) {
-                    return value
-            }
-            if container.decodeNil() {
-                    return JSONNull()
-            }
-            throw decodingError(forCodingPath: container.codingPath)
-    }
-
-    static func decode(from container: inout UnkeyedDecodingContainer) throws -> Any {
-            if let value = try? container.decode(Bool.self) {
-                    return value
-            }
-            if let value = try? container.decode(Int64.self) {
-                    return value
-            }
-            if let value = try? container.decode(Double.self) {
-                    return value
-            }
-            if let value = try? container.decode(String.self) {
-                    return value
-            }
-            if let value = try? container.decodeNil() {
-                    if value {
-                            return JSONNull()
-                    }
-            }
-            if var container = try? container.nestedUnkeyedContainer() {
-                    return try decodeArray(from: &container)
-            }
-            if var container = try? container.nestedContainer(keyedBy: JSONCodingKey.self) {
-                    return try decodeDictionary(from: &container)
-            }
-            throw decodingError(forCodingPath: container.codingPath)
-    }
-
-    static func decode(from container: inout KeyedDecodingContainer<JSONCodingKey>, forKey key: JSONCodingKey) throws -> Any {
-            if let value = try? container.decode(Bool.self, forKey: key) {
-                    return value
-            }
-            if let value = try? container.decode(Int64.self, forKey: key) {
-                    return value
-            }
-            if let value = try? container.decode(Double.self, forKey: key) {
-                    return value
-            }
-            if let value = try? container.decode(String.self, forKey: key) {
-                    return value
-            }
-            if let value = try? container.decodeNil(forKey: key) {
-                    if value {
-                            return JSONNull()
-                    }
-            }
-            if var container = try? container.nestedUnkeyedContainer(forKey: key) {
-                    return try decodeArray(from: &container)
-            }
-            if var container = try? container.nestedContainer(keyedBy: JSONCodingKey.self, forKey: key) {
-                    return try decodeDictionary(from: &container)
-            }
-            throw decodingError(forCodingPath: container.codingPath)
-    }
-
-    static func decodeArray(from container: inout UnkeyedDecodingContainer) throws -> [Any] {
-            var arr: [Any] = []
-            while !container.isAtEnd {
-                    let value = try decode(from: &container)
-                    arr.append(value)
-            }
-            return arr
-    }
-
-    static func decodeDictionary(from container: inout KeyedDecodingContainer<JSONCodingKey>) throws -> [String: Any] {
-            var dict = [String: Any]()
-            for key in container.allKeys {
-                    let value = try decode(from: &container, forKey: key)
-                    dict[key.stringValue] = value
-            }
-            return dict
-    }
-
-    static func encode(to container: inout UnkeyedEncodingContainer, array: [Any]) throws {
-            for value in array {
-                    if let value = value as? Bool {
-                            try container.encode(value)
-                    } else if let value = value as? Int64 {
-                            try container.encode(value)
-                    } else if let value = value as? Double {
-                            try container.encode(value)
-                    } else if let value = value as? String {
-                            try container.encode(value)
-                    } else if value is JSONNull {
-                            try container.encodeNil()
-                    } else if let value = value as? [Any] {
-                            var container = container.nestedUnkeyedContainer()
-                            try encode(to: &container, array: value)
-                    } else if let value = value as? [String: Any] {
-                            var container = container.nestedContainer(keyedBy: JSONCodingKey.self)
-                            try encode(to: &container, dictionary: value)
-                    } else {
-                            throw encodingError(forValue: value, codingPath: container.codingPath)
-                    }
-            }
-    }
-
-    static func encode(to container: inout KeyedEncodingContainer<JSONCodingKey>, dictionary: [String: Any]) throws {
-            for (key, value) in dictionary {
-                    let key = JSONCodingKey(stringValue: key)!
-                    if let value = value as? Bool {
-                            try container.encode(value, forKey: key)
-                    } else if let value = value as? Int64 {
-                            try container.encode(value, forKey: key)
-                    } else if let value = value as? Double {
-                            try container.encode(value, forKey: key)
-                    } else if let value = value as? String {
-                            try container.encode(value, forKey: key)
-                    } else if value is JSONNull {
-                            try container.encodeNil(forKey: key)
-                    } else if let value = value as? [Any] {
-                            var container = container.nestedUnkeyedContainer(forKey: key)
-                            try encode(to: &container, array: value)
-                    } else if let value = value as? [String: Any] {
-                            var container = container.nestedContainer(keyedBy: JSONCodingKey.self, forKey: key)
-                            try encode(to: &container, dictionary: value)
-                    } else {
-                            throw encodingError(forValue: value, codingPath: container.codingPath)
-                    }
-            }
-    }
-
-    static func encode(to container: inout SingleValueEncodingContainer, value: Any) throws {
-            if let value = value as? Bool {
-                    try container.encode(value)
-            } else if let value = value as? Int64 {
-                    try container.encode(value)
-            } else if let value = value as? Double {
-                    try container.encode(value)
-            } else if let value = value as? String {
-                    try container.encode(value)
-            } else if value is JSONNull {
-                    try container.encodeNil()
-            } else {
-                    throw encodingError(forValue: value, codingPath: container.codingPath)
-            }
-    }
-
-    public required init(from decoder: Decoder) throws {
-            if var arrayContainer = try? decoder.unkeyedContainer() {
-                    self.value = try JSONAny.decodeArray(from: &arrayContainer)
-            } else if var container = try? decoder.container(keyedBy: JSONCodingKey.self) {
-                    self.value = try JSONAny.decodeDictionary(from: &container)
-            } else {
-                    let container = try decoder.singleValueContainer()
-                    self.value = try JSONAny.decode(from: container)
-            }
-    }
-
-    public func encode(to encoder: Encoder) throws {
-            if let arr = self.value as? [Any] {
-                    var container = encoder.unkeyedContainer()
-                    try JSONAny.encode(to: &container, array: arr)
-            } else if let dict = self.value as? [String: Any] {
-                    var container = encoder.container(keyedBy: JSONCodingKey.self)
-                    try JSONAny.encode(to: &container, dictionary: dict)
-            } else {
-                    var container = encoder.singleValueContainer()
-                    try JSONAny.encode(to: &container, value: self.value)
-            }
-    }
-}
+// quicktype's JSONAny/JSONNull helper suffix is intentionally replaced here.
+// See ../JSONAny.swift for the maintained Swift implementation.
diff --git a/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/JSONAny.swift b/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/JSONAny.swift
new file mode 100644
index 00000000..e7eb4e8a
--- /dev/null
+++ b/protocol/languages/swift/Sources/ShopifyCheckoutProtocol/JSONAny.swift
@@ -0,0 +1,302 @@
+// quicktype emits JSONAny/JSONNull helpers directly into Generated/Models.swift.
+// protocol/scripts/generate_models.mjs verifies that helper suffix by SHA, replaces
+// it with a marker comment, and relies on this file for the maintained implementation.
+// Keeping these types here lets Swift tooling lint, format, and type-check them.
+
+// MARK: - Encode/decode helpers
+
+public final class JSONNull: Codable, Hashable, Sendable {
+    public static func == (_: JSONNull, _: JSONNull) -> Bool {
+        return true
+    }
+
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(0)
+    }
+
+    public init() {}
+
+    public required init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        if !container.decodeNil() {
+            throw DecodingError.typeMismatch(
+                JSONNull.self,
+                DecodingError.Context(
+                    codingPath: decoder.codingPath,
+                    debugDescription: "Wrong type for JSONNull"
+                )
+            )
+        }
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encodeNil()
+    }
+}
+
+final class JSONCodingKey: CodingKey, Sendable {
+    let key: String
+
+    required init?(intValue _: Int) {
+        return nil
+    }
+
+    required init?(stringValue: String) {
+        key = stringValue
+    }
+
+    var intValue: Int? {
+        return nil
+    }
+
+    var stringValue: String {
+        return key
+    }
+}
+
+private enum JSONValue: Sendable {
+    case bool(Bool)
+    case int(Int64)
+    case double(Double)
+    case string(String)
+    case null
+    case array([JSONValue])
+    case object([String: JSONValue])
+
+    var value: Any {
+        switch self {
+        case let .bool(value):
+            return value
+        case let .int(value):
+            return value
+        case let .double(value):
+            return value
+        case let .string(value):
+            return value
+        case .null:
+            return JSONNull()
+        case let .array(values):
+            return values.map(\.value)
+        case let .object(values):
+            return values.mapValues { $0.value }
+        }
+    }
+}
+
+public final class JSONAny: Codable, Sendable {
+    private let storage: JSONValue
+
+    public var value: Any {
+        storage.value
+    }
+
+    private static func decodingError(forCodingPath codingPath: [CodingKey]) -> DecodingError {
+        let context = DecodingError.Context(codingPath: codingPath, debugDescription: "Cannot decode JSONAny")
+        return DecodingError.typeMismatch(JSONAny.self, context)
+    }
+
+    private static func decode(from container: SingleValueDecodingContainer) throws -> JSONValue {
+        if let value = try? container.decode(Bool.self) {
+            return .bool(value)
+        }
+        if let value = try? container.decode(Int64.self) {
+            return .int(value)
+        }
+        if let value = try? container.decode(Double.self) {
+            return .double(value)
+        }
+        if let value = try? container.decode(String.self) {
+            return .string(value)
+        }
+        if container.decodeNil() {
+            return .null
+        }
+        throw decodingError(forCodingPath: container.codingPath)
+    }
+
+    private static func decode(from container: inout UnkeyedDecodingContainer) throws -> JSONValue {
+        if let value = try? container.decode(Bool.self) {
+            return .bool(value)
+        }
+        if let value = try? container.decode(Int64.self) {
+            return .int(value)
+        }
+        if let value = try? container.decode(Double.self) {
+            return .double(value)
+        }
+        if let value = try? container.decode(String.self) {
+            return .string(value)
+        }
+        if let value = try? container.decodeNil() {
+            if value {
+                return .null
+            }
+        }
+        if var container = try? container.nestedUnkeyedContainer() {
+            return try decodeArray(from: &container)
+        }
+        if var container = try? container.nestedContainer(keyedBy: JSONCodingKey.self) {
+            return try decodeDictionary(from: &container)
+        }
+        throw decodingError(forCodingPath: container.codingPath)
+    }
+
+    private static func decode(
+        from container: inout KeyedDecodingContainer<JSONCodingKey>,
+        forKey key: JSONCodingKey
+    ) throws -> JSONValue {
+        if let value = try? container.decode(Bool.self, forKey: key) {
+            return .bool(value)
+        }
+        if let value = try? container.decode(Int64.self, forKey: key) {
+            return .int(value)
+        }
+        if let value = try? container.decode(Double.self, forKey: key) {
+            return .double(value)
+        }
+        if let value = try? container.decode(String.self, forKey: key) {
+            return .string(value)
+        }
+        if let value = try? container.decodeNil(forKey: key) {
+            if value {
+                return .null
+            }
+        }
+        if var container = try? container.nestedUnkeyedContainer(forKey: key) {
+            return try decodeArray(from: &container)
+        }
+        if var container = try? container.nestedContainer(keyedBy: JSONCodingKey.self, forKey: key) {
+            return try decodeDictionary(from: &container)
+        }
+        throw decodingError(forCodingPath: container.codingPath)
+    }
+
+    private static func decodeArray(from container: inout UnkeyedDecodingContainer) throws -> JSONValue {
+        var values: [JSONValue] = []
+        while !container.isAtEnd {
+            let value = try decode(from: &container)
+            values.append(value)
+        }
+        return .array(values)
+    }
+
+    private static func decodeDictionary(from container: inout KeyedDecodingContainer<JSONCodingKey>) throws -> JSONValue {
+        var values = [String: JSONValue]()
+        for key in container.allKeys {
+            let value = try decode(from: &container, forKey: key)
+            values[key.stringValue] = value
+        }
+        return .object(values)
+    }
+
+    private static func encode(to container: inout UnkeyedEncodingContainer, array: [JSONValue]) throws {
+        for value in array {
+            try encode(to: &container, value: value)
+        }
+    }
+
+    private static func encode(
+        to container: inout KeyedEncodingContainer<JSONCodingKey>,
+        dictionary: [String: JSONValue]
+    ) throws {
+        for (key, value) in dictionary {
+            let key = JSONCodingKey(stringValue: key)!
+            try encode(to: &container, value: value, forKey: key)
+        }
+    }
+
+    private static func encode(to container: inout SingleValueEncodingContainer, value: JSONValue) throws {
+        switch value {
+        case let .bool(value):
+            try container.encode(value)
+        case let .int(value):
+            try container.encode(value)
+        case let .double(value):
+            try container.encode(value)
+        case let .string(value):
+            try container.encode(value)
+        case .null:
+            try container.encodeNil()
+        case .array, .object:
+            throw EncodingError.invalidValue(
+                value.value,
+                EncodingError.Context(
+                    codingPath: container.codingPath,
+                    debugDescription: "Cannot encode nested JSON value in a single-value container"
+                )
+            )
+        }
+    }
+
+    private static func encode(to container: inout UnkeyedEncodingContainer, value: JSONValue) throws {
+        switch value {
+        case let .bool(value):
+            try container.encode(value)
+        case let .int(value):
+            try container.encode(value)
+        case let .double(value):
+            try container.encode(value)
+        case let .string(value):
+            try container.encode(value)
+        case .null:
+            try container.encodeNil()
+        case let .array(values):
+            var container = container.nestedUnkeyedContainer()
+            try encode(to: &container, array: values)
+        case let .object(values):
+            var container = container.nestedContainer(keyedBy: JSONCodingKey.self)
+            try encode(to: &container, dictionary: values)
+        }
+    }
+
+    private static func encode(
+        to container: inout KeyedEncodingContainer<JSONCodingKey>,
+        value: JSONValue,
+        forKey key: JSONCodingKey
+    ) throws {
+        switch value {
+        case let .bool(value):
+            try container.encode(value, forKey: key)
+        case let .int(value):
+            try container.encode(value, forKey: key)
+        case let .double(value):
+            try container.encode(value, forKey: key)
+        case let .string(value):
+            try container.encode(value, forKey: key)
+        case .null:
+            try container.encodeNil(forKey: key)
+        case let .array(values):
+            var container = container.nestedUnkeyedContainer(forKey: key)
+            try encode(to: &container, array: values)
+        case let .object(values):
+            var container = container.nestedContainer(keyedBy: JSONCodingKey.self, forKey: key)
+            try encode(to: &container, dictionary: values)
+        }
+    }
+
+    public required init(from decoder: Decoder) throws {
+        if var arrayContainer = try? decoder.unkeyedContainer() {
+            storage = try JSONAny.decodeArray(from: &arrayContainer)
+        } else if var container = try? decoder.container(keyedBy: JSONCodingKey.self) {
+            storage = try JSONAny.decodeDictionary(from: &container)
+        } else {
+            let container = try decoder.singleValueContainer()
+            storage = try JSONAny.decode(from: container)
+        }
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        switch storage {
+        case let .array(values):
+            var container = encoder.unkeyedContainer()
+            try JSONAny.encode(to: &container, array: values)
+        case let .object(values):
+            var container = encoder.container(keyedBy: JSONCodingKey.self)
+            try JSONAny.encode(to: &container, dictionary: values)
+        default:
+            var container = encoder.singleValueContainer()
+            try JSONAny.encode(to: &container, value: storage)
+        }
+    }
+}
diff --git a/protocol/scripts/generate_models.mjs b/protocol/scripts/generate_models.mjs
index cf90f861..6ea0583f 100755
--- a/protocol/scripts/generate_models.mjs
+++ b/protocol/scripts/generate_models.mjs
@@ -22,6 +22,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+import crypto from "node:crypto";
 import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
@@ -37,6 +38,16 @@ import {
 
 const SCHEMA_SOURCE_DIR = path.join(PROTOCOL_DIR, "schemas");
 const SERVICES_DIR = path.join(PROTOCOL_DIR, "services", "shopping");
+const SWIFT_JSON_HELPER_MARKER = "// MARK: - Encode/decode helpers";
+const SWIFT_JSON_HELPER_REPLACEMENT = `// MARK: - Encode/decode helpers
+// quicktype's JSONAny/JSONNull helper suffix is intentionally replaced here.
+// See ../JSONAny.swift for the maintained Swift implementation.
+`;
+// quicktype 23.2.6's Swift helper suffix for:
+// --lang swift --swift-5-support --access-level public --sendable
+// Guarding the whole suffix keeps this normalization fail-fast if quicktype fixes
+// or changes the helper block instead of silently clobbering future output.
+const QUICKTYPE_23_2_6_SWIFT_JSON_HELPER_SHA256 = "02b7721a424fdb5a586a773116130f0b273551f9bfd5d9111a1c700581ec5e7e";
 
 function usage() {
   console.error("Usage: generate_models.sh --lang <kotlin|swift|typescript> [--output <path>]");
@@ -176,9 +187,10 @@ async function prepareCodegenSchemas(tempDir) {
   // Message discriminators are defined across the message variant schemas. Give
   // each variant the same local title so quicktype emits a single MessageType symbol.
   for (const messageSchema of ["message_error", "message_warning", "message_info"]) {
-    const schema = await readJson(path.join(specDir, "types", `${messageSchema}.json`));
+    const schemaPath = path.join(schemaDir, "common", "types", `${messageSchema}.json`);
+    const schema = await readJson(schemaPath);
     schema.properties.type.title = "MessageType";
-    await writeJson(path.join(specDir, "types", `${messageSchema}.json`), schema);
+    await writeJson(schemaPath, schema);
   }
 
   // Extension schemas bring in repeated generic property names like `type` and
@@ -268,7 +280,7 @@ function commonSchemaSources(specDir) {
     "--src",
     path.join(specDir, "order.json"),
     "--src",
-    path.join(specDir, "types", "error_response.json"),
+    path.join(specDir, "..", "common", "types", "error_response.json"),
     "--src",
     path.join(specDir, "instruments_change_result.json"),
     "--src",
@@ -332,7 +344,25 @@ async function generateSwift(specDir, output) {
     output,
   ]);
 
-  await normalizeGeneratedFile(output);
+  await normalizeGeneratedFile(output, (source) => {
+    // quicktype's --sendable option marks generated models as Sendable, but quicktype 23.2.6
+    // still emits dynamic JSON helper types that are not fully Swift 6 concurrency-safe.
+    // Drop only the exact helper suffix quicktype 23.2.6 emits. Maintained helper
+    // implementations live in ShopifyCheckoutProtocol/JSONAny.swift so Swift tooling can
+    // lint, format, and type-check them normally.
+    const helperStart = source.indexOf(SWIFT_JSON_HELPER_MARKER);
+    if (helperStart === -1) {
+      throw new Error("Swift JSON helper normalization failed; quicktype output may have changed");
+    }
+
+    const generatedHelper = source.slice(helperStart);
+    const generatedHelperHash = crypto.createHash("sha256").update(generatedHelper).digest("hex");
+    if (generatedHelperHash !== QUICKTYPE_23_2_6_SWIFT_JSON_HELPER_SHA256) {
+      throw new Error(`Swift JSON helper normalization failed; quicktype helper output changed (sha256: ${generatedHelperHash})`);
+    }
+
+    return `${source.slice(0, helperStart)}${SWIFT_JSON_HELPER_REPLACEMENT}`;
+  });
 }
 
 async function generateTypescript(specDir, output) {