diff --git a/StripeCardScan/StripeCardScanTests/Unit/API Bindings/ScanStatsPayloadAPIBindingsTests.swift b/StripeCardScan/StripeCardScanTests/Unit/API Bindings/ScanStatsPayloadAPIBindingsTests.swift
index 22a4123c9e01..cb4d62e48856 100644
--- a/StripeCardScan/StripeCardScanTests/Unit/API Bindings/ScanStatsPayloadAPIBindingsTests.swift	
+++ b/StripeCardScan/StripeCardScanTests/Unit/API Bindings/ScanStatsPayloadAPIBindingsTests.swift	
@@ -74,7 +74,7 @@ class ScanStatsPayloadAPIBindingsTests: XCTestCase {
     /// Check that scan stats tasks is encoded properly
     func testScanStatsTasks() throws {
         /// Check that scan stats tasks is encoded properly
-        let jsonDictionary = try scanStatsTasks.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(scanStatsTasks)
         let tasksDictionary = jsonDictionary["tasks"] as! [String: Any]
         let repeatingTaskDictionary = jsonDictionary["repeating_tasks"] as! [String: Any]
 
@@ -85,7 +85,7 @@ class ScanStatsPayloadAPIBindingsTests: XCTestCase {
     /// Check that non repeating tasks are encoded properly
     func testNonRepeatingTasks() throws {
         /// Check that the JSON dictionary is formed properly
-        let jsonDictionary = try nonRepeatingTasks.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(nonRepeatingTasks)
         let jsonCameraPermissions = jsonDictionary["camera_permission"] as! [[String: Any]]
         XCTAssertEqual(jsonCameraPermissions.count, 1)
         XCTAssertEqual(jsonCameraPermissions[0]["result"] as! String, "success")
@@ -111,7 +111,7 @@ class ScanStatsPayloadAPIBindingsTests: XCTestCase {
     /// Check that repeating tasks are encoded properly
     func testRepeatingTasks() throws {
         /// Check that the JSON dictionary is formed properly
-        let jsonDictionary = try repeatingTasks.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(repeatingTasks)
         let jsonMainLoop = jsonDictionary["main_loop_images_processed"] as! [String: Any]
         XCTAssertEqual(jsonMainLoop["executions"] as? Int, -1)
     }
@@ -130,7 +130,7 @@ class ScanStatsPayloadAPIBindingsTests: XCTestCase {
                 scanStats: scanStatsTasks
             )
         )
-        let jsonDictionary = try scanStatsPayload.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(scanStatsPayload)
         /// Create query string
         let queryString = URLEncoder.queryString(from: jsonDictionary)
 
diff --git a/StripeCardScan/StripeCardScanTests/Unit/API Bindings/VerifyFramesAPIBindingsTests.swift b/StripeCardScan/StripeCardScanTests/Unit/API Bindings/VerifyFramesAPIBindingsTests.swift
index 64df6671f8af..311f945de308 100644
--- a/StripeCardScan/StripeCardScanTests/Unit/API Bindings/VerifyFramesAPIBindingsTests.swift	
+++ b/StripeCardScan/StripeCardScanTests/Unit/API Bindings/VerifyFramesAPIBindingsTests.swift	
@@ -26,7 +26,7 @@ class VerifyFramesAPIBindingsTests: XCTestCase {
         )
 
         /// encodeJSONDictionary used when forming the request body
-        let jsonDictionary = try verifyFrames.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(verifyFrames)
 
         XCTAssertEqual(jsonDictionary["client_secret"] as! String, CIVIntentMockData.clientSecret)
         XCTAssertEqual(
@@ -59,7 +59,7 @@ class VerifyFramesAPIBindingsTests: XCTestCase {
         )
 
         /// encodeJSONDictionary used when forming the request body
-        let jsonDictionary = try verificationFramesData.encodeJSONDictionary()
+        let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(verificationFramesData)
         let jsonDictionaryViewfinderMargins = jsonDictionary["viewfinder_margins"] as! [String: Any]
 
         XCTAssertEqual(jsonDictionary["image_data"] as! String, "aW1hZ2VfZGF0YQ==")
diff --git a/StripeCore/StripeCore/Source/API Bindings/STPAPIClient.swift b/StripeCore/StripeCore/Source/API Bindings/STPAPIClient.swift
index 1f57054e779a..507982da34ed 100644
--- a/StripeCore/StripeCore/Source/API Bindings/STPAPIClient.swift	
+++ b/StripeCore/StripeCore/Source/API Bindings/STPAPIClient.swift	
@@ -494,7 +494,7 @@ extension STPAPIClient {
         completion: @escaping (Result<O, Error>) -> Void
     ) {
         do {
-            let jsonDictionary = try object.encodeJSONDictionary()
+            let jsonDictionary = try StripeJSONEncoder().encodeJSONDictionary(object)
             let formData = URLEncoder.queryString(from: jsonDictionary).data(using: .utf8)
             var request = configuredRequest(
                 for: url,
diff --git a/StripeCore/StripeCore/Source/API Bindings/StripeError.swift b/StripeCore/StripeCore/Source/API Bindings/StripeError.swift
index f4a4083cac50..2f1b40fa1346 100644
--- a/StripeCore/StripeCore/Source/API Bindings/StripeError.swift	
+++ b/StripeCore/StripeCore/Source/API Bindings/StripeError.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Error codes returned from STPAPIClient.
-@_spi(STP) public enum StripeError: Error {
+@_spi(STP) @frozen public enum StripeError: Error {
     /// The server returned an API error.
     case apiError(StripeAPIError)
 
diff --git a/StripeCore/StripeCore/Source/Analytics/STPAnalyticEvent.swift b/StripeCore/StripeCore/Source/Analytics/STPAnalyticEvent.swift
index 0323c8d1d9ba..1ad9a06114f6 100644
--- a/StripeCore/StripeCore/Source/Analytics/STPAnalyticEvent.swift
+++ b/StripeCore/StripeCore/Source/Analytics/STPAnalyticEvent.swift
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Enumeration of all the analytic events logged by our SDK.
-@_spi(STP) public enum STPAnalyticEvent: String {
+@_spi(STP) @frozen public enum STPAnalyticEvent: String {
     // MARK: - Payment Creation
     case tokenCreation = "stripeios.token_creation"
 
diff --git a/StripeCore/StripeCore/Source/Coder/StripeCodable.swift b/StripeCore/StripeCore/Source/Coder/StripeCodable.swift
index 03e9206a810d..659ef75f93c3 100644
--- a/StripeCore/StripeCore/Source/Coder/StripeCodable.swift
+++ b/StripeCore/StripeCore/Source/Coder/StripeCodable.swift
@@ -64,10 +64,6 @@ extension UnknownFieldsDecodable {
             self._allResponseFieldsStorage!.storage = newValue
         }
     }
-
-    static func decodedObject(jsonData: Data) throws -> Self {
-        return try StripeJSONDecoder.decode(jsonData: jsonData)
-    }
 }
 
 extension UnknownFieldsEncodable {
@@ -97,16 +93,6 @@ extension UnknownFieldsEncodable {
     }
 }
 
-extension Encodable {
-    @_spi(STP) public func encodeJSONDictionary(includingUnknownFields: Bool = true) throws -> [String: Any] {
-        let encoder = StripeJSONEncoder()
-        return try encoder.encodeJSONDictionary(
-            self,
-            includingUnknownFields: includingUnknownFields
-        )
-    }
-}
-
 @_spi(STP) public enum UnknownFieldsCodableFloats: String {
     case PositiveInfinity = "Inf"
     case NegativeInfinity = "-Inf"
diff --git a/StripeCore/StripeCore/Source/Coder/StripeJSONEncoder.swift b/StripeCore/StripeCore/Source/Coder/StripeJSONEncoder.swift
index fd85a1d15b59..7ff2d9478517 100644
--- a/StripeCore/StripeCore/Source/Coder/StripeJSONEncoder.swift
+++ b/StripeCore/StripeCore/Source/Coder/StripeJSONEncoder.swift
@@ -14,6 +14,8 @@ import Foundation
 
     @_spi(STP) public var outputFormatting: JSONSerialization.WritingOptions = []
 
+    @_spi(STP) public init() {}
+
     @_spi(STP) public func encode<T>(_ value: T, includingUnknownFields: Bool = true) throws -> Data
     where T: Encodable {
         var outputFormatting = self.outputFormatting
@@ -30,7 +32,7 @@ import Foundation
             )
         } else {
             return try JSONSerialization.data(
-                withJSONObject: castToNSObject(value),
+                withJSONObject: StripeEncodingUtils.castToNSObject(userInfo: userInfo, value),
                 options: outputFormatting
             )
         }
@@ -55,7 +57,7 @@ import Foundation
 
         // Encode the object to JSON data
         let jsonData = try JSONSerialization.data(
-            withJSONObject: castToNSObject(value),
+            withJSONObject: StripeEncodingUtils.castToNSObject(userInfo: userInfo, value),
             options: outputFormatting
         )
 
@@ -73,9 +75,6 @@ import Foundation
     }
 }
 
-// Make sure StripeJSONEncoder can call castToNSObject
-extension StripeJSONEncoder: StripeEncodingContainer {}
-
 class _stpinternal_JSONEncoder: Encoder {
     var codingPath: [CodingKey] = []
 
@@ -131,8 +130,7 @@ class _stpinternal_JSONEncoder: Encoder {
     }
 }
 
-struct STPKeyedEncodingContainer<K>: StripeEncodingContainer, KeyedEncodingContainerProtocol
-where K: CodingKey {
+struct STPKeyedEncodingContainer<K>: KeyedEncodingContainerProtocol where K: CodingKey {
     var codingPath: [CodingKey]
 
     typealias Key = K
@@ -155,59 +153,59 @@ where K: CodingKey {
     }
 
     mutating func encode(_ value: Bool, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: String, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Double, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Float, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Int, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Int8, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Int16, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Int32, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: Int64, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: UInt, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: UInt8, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: UInt16, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: UInt32, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode(_ value: UInt64, forKey key: K) throws {
-        try encode(object: castToNSObject(value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value), forKey: key)
     }
 
     mutating func encode<T>(_ value: T, forKey key: K) throws where T: Encodable {
@@ -219,7 +217,7 @@ where K: CodingKey {
         if let seValue = value as? UnknownFieldsEncodable {
             seValue.applyUnknownFieldEncodingTransforms(userInfo: userInfo, codingPath: newPath)
         }
-        try encode(object: castToNSObject(codingPath: newPath, value), forKey: key)
+        try encode(object: StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: newPath, value), forKey: key)
     }
 
     mutating func nestedContainer<NestedKey>(
@@ -264,7 +262,7 @@ where K: CodingKey {
     }
 }
 
-struct STPUnkeyedEncodingContainer: UnkeyedEncodingContainer, StripeEncodingContainer {
+struct STPUnkeyedEncodingContainer: UnkeyedEncodingContainer {
     var codingPath: [CodingKey]
 
     var count: Int = 0
@@ -278,72 +276,72 @@ struct STPUnkeyedEncodingContainer: UnkeyedEncodingContainer, StripeEncodingCont
     }
 
     mutating func encode(_ value: Bool) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: String) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Double) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Float) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Int) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Int8) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Int16) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Int32) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: Int64) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: UInt) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: UInt8) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: UInt16) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: UInt32) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
     mutating func encode(_ value: UInt64) throws {
-        try array.add(castToNSObject(value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
         count += 1
     }
 
@@ -356,7 +354,7 @@ struct STPUnkeyedEncodingContainer: UnkeyedEncodingContainer, StripeEncodingCont
         if let seValue = value as? UnknownFieldsEncodable {
             seValue.applyUnknownFieldEncodingTransforms(userInfo: userInfo, codingPath: newPath)
         }
-        try array.add(castToNSObject(codingPath: newPath, value))
+        try array.add(StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: newPath, value))
 
         count += 1
     }
@@ -401,7 +399,7 @@ struct STPUnkeyedEncodingContainer: UnkeyedEncodingContainer, StripeEncodingCont
 
 }
 
-struct STPSingleValueEncodingContainer: SingleValueEncodingContainer, StripeEncodingContainer {
+struct STPSingleValueEncodingContainer: SingleValueEncodingContainer {
     var codingPath: [CodingKey]
 
     var encodingBlock: (NSObject) -> Void
@@ -412,59 +410,59 @@ struct STPSingleValueEncodingContainer: SingleValueEncodingContainer, StripeEnco
     }
 
     mutating func encode(_ value: Bool) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: String) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Double) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Float) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Int) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Int8) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Int16) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Int32) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: Int64) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: UInt) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: UInt8) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: UInt16) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: UInt32) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode(_ value: UInt64) throws {
-        encodingBlock(try castToNSObject(value))
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 
     mutating func encode<T>(_ value: T) throws where T: Encodable {
@@ -475,19 +473,17 @@ struct STPSingleValueEncodingContainer: SingleValueEncodingContainer, StripeEnco
         if let seValue = value as? UnknownFieldsEncodable {
             seValue.applyUnknownFieldEncodingTransforms(userInfo: userInfo, codingPath: codingPath)
         }
-        encodingBlock(try castToNSObject(value))
-    }
-}
-
-protocol StripeEncodingContainer {
-    var userInfo: [CodingUserInfoKey: Any] {
-        get set
+        encodingBlock(try StripeEncodingUtils.castToNSObject(userInfo: userInfo, codingPath: codingPath, value))
     }
 }
 
-extension StripeEncodingContainer {
-    fileprivate func castToNSObject<T>(codingPath: [CodingKey] = [], _ value: T) throws -> NSObject
-    where T: Encodable {
+/// Utility for encoding Swift values to NSObject types compatible with NSJSONSerialization
+enum StripeEncodingUtils {
+    static func castToNSObject<T>(
+        userInfo: [CodingUserInfoKey: Any],
+        codingPath: [CodingKey] = [],
+        _ value: T
+    ) throws -> NSObject where T: Encodable {
         switch value {
         case let n as Bool:
             return n as NSObject
diff --git a/StripeCore/StripeCore/Source/Coder/UnknownFields.swift b/StripeCore/StripeCore/Source/Coder/UnknownFields.swift
index 281bfbe4456a..0dc1759a7670 100644
--- a/StripeCore/StripeCore/Source/Coder/UnknownFields.swift
+++ b/StripeCore/StripeCore/Source/Coder/UnknownFields.swift
@@ -77,7 +77,8 @@ extension UnknownFieldsDecodable {
             // When the object is later re-encoded, the additionalParameters will
             // be re-added to the encoded JSON.
             if var encodableValue = object as? UnknownFieldsEncodable {
-                let encodedDictionary = try encodableValue.encodeJSONDictionary(
+                let encodedDictionary = try StripeJSONEncoder().encodeJSONDictionary(
+                    encodableValue,
                     includingUnknownFields: false
                 )
                 encodableValue.additionalParameters = jsonDictionary.subtracting(encodedDictionary)
diff --git a/StripeCore/StripeCore/Source/Connections Bindings/LinkMode.swift b/StripeCore/StripeCore/Source/Connections Bindings/LinkMode.swift
index a4e567e10042..92f08997fe5f 100644
--- a/StripeCore/StripeCore/Source/Connections Bindings/LinkMode.swift	
+++ b/StripeCore/StripeCore/Source/Connections Bindings/LinkMode.swift	
@@ -7,7 +7,7 @@
 
 import Foundation
 
-@_spi(STP) public enum LinkMode: String {
+@_spi(STP) @frozen public enum LinkMode: String {
     case linkPaymentMethod = "LINK_PAYMENT_METHOD"
     case passthrough = "PASSTHROUGH"
     case linkCardBrand = "LINK_CARD_BRAND"
diff --git a/StripeCore/StripeCore/Source/Helpers/STPError.swift b/StripeCore/StripeCore/Source/Helpers/STPError.swift
index a4bf66abc3d0..054afad08003 100644
--- a/StripeCore/StripeCore/Source/Helpers/STPError.swift
+++ b/StripeCore/StripeCore/Source/Helpers/STPError.swift
@@ -297,7 +297,7 @@ extension NSError {
 ///
 /// These values will come back in the error `userInfo` dictionary
 /// under the `STPCardErrorCodeKey` key.
-public enum STPCardErrorCode: String {
+@frozen public enum STPCardErrorCode: String {
     /// The card number is not a valid credit card number.
     case invalidNumber = "com.stripe.lib:InvalidNumber"
     /// The card has an invalid expiration month.
diff --git a/StripeCore/StripeCore/Source/Helpers/STPNumericStringValidator.swift b/StripeCore/StripeCore/Source/Helpers/STPNumericStringValidator.swift
index 6f84c71c2278..6197453c3903 100644
--- a/StripeCore/StripeCore/Source/Helpers/STPNumericStringValidator.swift
+++ b/StripeCore/StripeCore/Source/Helpers/STPNumericStringValidator.swift
@@ -8,7 +8,7 @@
 
 import Foundation
 
-@_spi(STP) public enum STPTextValidationState: Int {
+@_spi(STP) @frozen public enum STPTextValidationState: Int {
     case empty
     case incomplete
     case complete
diff --git a/StripeCore/StripeCoreTests/API Bindings/StripeCodableTest.swift b/StripeCore/StripeCoreTests/API Bindings/StripeCodableTest.swift
index b03b035f163f..e3abf8eb94b6 100644
--- a/StripeCore/StripeCoreTests/API Bindings/StripeCodableTest.swift	
+++ b/StripeCore/StripeCoreTests/API Bindings/StripeCodableTest.swift	
@@ -71,7 +71,7 @@ class StripeAPIRequestTest: APIStubbedTestCase {
         completion: @escaping ([String: Any], Result<T, Error>) -> Void
     ) {
         let e = expectation(description: "Request completed")
-        let encodedDict = try! codable.encodeJSONDictionary()
+        let encodedDict = try! StripeJSONEncoder().encodeJSONDictionary(codable)
         let encodedData = try? JSONSerialization.data(withJSONObject: encodedDict, options: [])
 
         let apiClient = stubbedAPIClient()
@@ -163,7 +163,7 @@ class StripeAPIRequestTest: APIStubbedTestCase {
                 resultObject.nested!.deeplyNested!.deeplyNestedProperty,
                 codable.nested!.deeplyNested!.deeplyNestedProperty
             )
-            let newDictionary = try! resultObject.encodeJSONDictionary() as NSDictionary
+            let newDictionary = try! StripeJSONEncoder().encodeJSONDictionary(resultObject) as NSDictionary
             XCTAssert(newDictionary.isEqual(to: codableDict))
         }
     }
@@ -193,7 +193,7 @@ class StripeAPIRequestTest: APIStubbedTestCase {
                 resultObject.nested!.deeplyNested!.deeplyNestedProperty,
                 codable.nested!.deeplyNested!.deeplyNestedProperty
             )
-            let newDictionary = try! resultObject.encodeJSONDictionary() as NSDictionary
+            let newDictionary = try! StripeJSONEncoder().encodeJSONDictionary(resultObject) as NSDictionary
             XCTAssert(newDictionary.isEqual(to: codableDict))
             XCTAssertEqual(
                 resultObject.nested!.nestedProperty,
diff --git a/StripeFinancialConnections/StripeFinancialConnections/Source/API Bindings/FinancialConnectionsAsyncAPIClient.swift b/StripeFinancialConnections/StripeFinancialConnections/Source/API Bindings/FinancialConnectionsAsyncAPIClient.swift
index b2734d3ebc4a..2dbae9e3468f 100644
--- a/StripeFinancialConnections/StripeFinancialConnections/Source/API Bindings/FinancialConnectionsAsyncAPIClient.swift	
+++ b/StripeFinancialConnections/StripeFinancialConnections/Source/API Bindings/FinancialConnectionsAsyncAPIClient.swift	
@@ -894,7 +894,7 @@ extension FinancialConnectionsAsyncAPIClient {
         }
 
         if let clientAttributionMetadata {
-            parameters["client_attribution_metadata"] = try clientAttributionMetadata.encodeJSONDictionary()
+            parameters["client_attribution_metadata"] = try StripeJSONEncoder().encodeJSONDictionary(clientAttributionMetadata)
         }
 
         return try await post(endpoint: .paymentDetails, parameters: parameters)
@@ -932,7 +932,7 @@ extension FinancialConnectionsAsyncAPIClient {
         }
 
         if let clientAttributionMetadata {
-            parameters["client_attribution_metadata"] = try clientAttributionMetadata.encodeJSONDictionary()
+            parameters["client_attribution_metadata"] = try StripeJSONEncoder().encodeJSONDictionary(clientAttributionMetadata)
         }
 
         let parametersWithFraudDetection = await updateAndApplyFraudDetection(to: parameters)
@@ -966,7 +966,7 @@ extension FinancialConnectionsAsyncAPIClient {
         }
 
         if let clientAttributionMetadata {
-            parameters["client_attribution_metadata"] = try clientAttributionMetadata.encodeJSONDictionary()
+            parameters["client_attribution_metadata"] = try StripeJSONEncoder().encodeJSONDictionary(clientAttributionMetadata)
         }
 
         let parametersWithFraudDetection = await updateAndApplyFraudDetection(to: parameters)
diff --git a/StripeIdentity/StripeIdentityTests/Unit/API Bindings/IdentityAPIClientTest.swift b/StripeIdentity/StripeIdentityTests/Unit/API Bindings/IdentityAPIClientTest.swift
index 5330ee908035..5eed135f800d 100644
--- a/StripeIdentity/StripeIdentityTests/Unit/API Bindings/IdentityAPIClientTest.swift	
+++ b/StripeIdentity/StripeIdentityTests/Unit/API Bindings/IdentityAPIClientTest.swift	
@@ -77,7 +77,7 @@ final class IdentityAPIClientTest: APIStubbedTestCase {
     func testUpdateVerificationPageData() throws {
         let mockVerificationData = VerificationPageDataUpdateMock.default
         let encodedMockVerificationData = URLEncoder.queryString(
-            from: try mockVerificationData.encodeJSONDictionary()
+            from: try StripeJSONEncoder().encodeJSONDictionary(mockVerificationData)
         )
 
         let mockVerificationPageData = VerificationPageDataMock.response200
diff --git a/StripeIdentity/StripeIdentityTests/Unit/API Bindings/TruncatedDecimalTest.swift b/StripeIdentity/StripeIdentityTests/Unit/API Bindings/TruncatedDecimalTest.swift
index ab665f0f234d..2fb1ab2eca73 100644
--- a/StripeIdentity/StripeIdentityTests/Unit/API Bindings/TruncatedDecimalTest.swift	
+++ b/StripeIdentity/StripeIdentityTests/Unit/API Bindings/TruncatedDecimalTest.swift	
@@ -42,7 +42,7 @@ extension TruncatedDecimalTest {
         // wrapped in quotations or represented as a nested container
         let container = Container(number: truncatedDecimal)
 
-        let jsonDict = try container.encodeJSONDictionary()
+        let jsonDict = try StripeJSONEncoder().encodeJSONDictionary(container)
         let queryString = URLEncoder.queryString(from: jsonDict)
         XCTAssertEqual(
             queryString,
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkPaymentMethodType.swift b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkPaymentMethodType.swift
index c2098ca584d1..ebc8fe4e56fb 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkPaymentMethodType.swift	
+++ b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkPaymentMethodType.swift	
@@ -7,7 +7,7 @@
 
 import Foundation
 
-@_spi(STP) public enum LinkPaymentMethodType: String, CaseIterable {
+@_spi(STP) @frozen public enum LinkPaymentMethodType: String, CaseIterable {
     case card = "CARD"
     case bankAccount = "BANK_ACCOUNT"
 }
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkRequestSurface.swift b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkRequestSurface.swift
index 858e41c294d6..e8ea0c11956d 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkRequestSurface.swift	
+++ b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/Link/LinkRequestSurface.swift	
@@ -7,7 +7,7 @@
 
 import Foundation
 
-@_spi(STP) public enum LinkRequestSurface: String {
+@_spi(STP) @frozen public enum LinkRequestSurface: String {
     /// Used for requests from the `StripePaymentSheet` SDK.
     case paymentElement = "ios_payment_element"
     /// Used for requests from the `StripeCryptoOnramp` SDK.
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/v1-elements-sessions/ExperimentData.swift b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/v1-elements-sessions/ExperimentData.swift
index 58f33fe8eed2..97c5336af199 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/v1-elements-sessions/ExperimentData.swift	
+++ b/StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/v1-elements-sessions/ExperimentData.swift	
@@ -7,7 +7,7 @@
 
 import Foundation
 
-@_spi(STP) public enum ExperimentGroup: String {
+@_spi(STP) @frozen public enum ExperimentGroup: String {
     case control
     case treatment
     case holdback
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerAdapter/CustomerPaymentOption.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerAdapter/CustomerPaymentOption.swift
index b90b9dc3ab66..1ac91281d08e 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerAdapter/CustomerPaymentOption.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerAdapter/CustomerPaymentOption.swift
@@ -6,7 +6,7 @@
 import Foundation
 
 /// A representation of a Payment Method option, used for persisting the user's default payment method.
-public enum CustomerPaymentOption: Equatable {
+@frozen public enum CustomerPaymentOption: Equatable {
     /// The user's default payment method is Apple Pay.
     /// This is not a specific Apple Pay card. Stripe will present an Apple Pay sheet to the user.
     case applePay
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerSheet/CustomerSheetError.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerSheet/CustomerSheetError.swift
index e964ff64ddba..c143985f9948 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerSheet/CustomerSheetError.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/CustomerSheet/CustomerSheetError.swift
@@ -7,7 +7,7 @@ import Foundation
 @_spi(STP) import StripeCore
 import StripePayments
 
-public enum CustomerSheetError: Error {
+@frozen public enum CustomerSheetError: Error {
     /// Error while fetching saved payment methods attached to a customer
     case errorFetchingSavedPaymentMethods(Error)
     /// Error if an unsupported payment method type is specified
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/CardSection/HostedSurface.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/CardSection/HostedSurface.swift
index 8bf92f8db6a2..0f73dbd55117 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/CardSection/HostedSurface.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/CardSection/HostedSurface.swift
@@ -9,7 +9,7 @@ import Foundation
 @_spi(STP) import StripeCore
 
 // Used to indicate if this card section is being used by either PaymentSheet or CustomerSheet
-@_spi(STP) public enum HostedSurface {
+@_spi(STP) @frozen public enum HostedSurface {
     case paymentSheet
     case customerSheet
 
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/PaymentMethodElement/PaymentMethodElement.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/PaymentMethodElement/PaymentMethodElement.swift
index 574fb1b88ca0..c5f2d52b0fe9 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/PaymentMethodElement/PaymentMethodElement.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Elements/PaymentMethodElement/PaymentMethodElement.swift
@@ -24,9 +24,12 @@ protocol PaymentMethodElement: Element {
     func updateParams(params: IntentConfirmParams) -> IntentConfirmParams?
 }
 
-extension PaymentMethodElement {
-    func clearTextFields() {
-        for element in getAllUnwrappedSubElements() {
+// MARK: - PaymentMethodElement utilities
+/// Utility methods for working with PaymentMethodElements
+enum PaymentMethodElementUtils {
+    /// Clears all text fields within an element hierarchy
+    static func clearTextFields(in element: Element) {
+        for element in element.getAllUnwrappedSubElements() {
             if let element = element as? TextFieldElement {
                 element.setText("")
             } else if let element = element as? CVCRecollectionElement {
@@ -34,6 +37,18 @@ extension PaymentMethodElement {
             }
         }
     }
+
+    /// Get the mandate text from an element hierarchy, if available
+    /// - Note: Assumes mandates are SimpleMandateElement
+    static func getMandateText(from element: Element) -> NSAttributedString? {
+        guard let mandateText = element.getAllUnwrappedSubElements()
+            .compactMap({ $0 as? SimpleMandateElement })
+            .first?.mandateTextView.attributedText,
+              !mandateText.string.isEmpty else {
+            return nil
+        }
+        return mandateText
+    }
 }
 
 // MARK: - Default implementations
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/EmbeddedPaymentElement+Internal.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/EmbeddedPaymentElement+Internal.swift
index eab734760034..9b6e18786062 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/EmbeddedPaymentElement+Internal.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/EmbeddedPaymentElement+Internal.swift
@@ -601,7 +601,7 @@ extension EmbeddedPaymentElement {
         // However: When `rowSelectionBehavior` is `immediateAction` and `embeddedViewDisplaysMandateText` is `true` and the customer selects a PM that has no form but has a mandate, there's a problem.
         // We'd normally show the mandate in the embedded view, but `immediateAction` implies the merchant will immediately confirm or move the customer to a different screen before they can see or consent to the mandate.
         // We therefore show a form with the mandate text and proceed as normal as if it were any other PM with a form (customer can continue or confirm in the sheet).
-        let paymentMethodHasNoFormAndHasAMandate = form.collectsUserInput == false && form.getMandateText() != nil
+        let paymentMethodHasNoFormAndHasAMandate = form.collectsUserInput == false && PaymentMethodElementUtils.getMandateText(from: form) != nil
         if
             case .immediateAction = configuration.rowSelectionBehavior,
             configuration.embeddedViewDisplaysMandateText,
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/MandateTextProvider.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/MandateTextProvider.swift
index d5229b829f98..fab27da73728 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/MandateTextProvider.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Embedded/MandateTextProvider.swift
@@ -84,7 +84,7 @@ class VerticalListMandateProvider: MandateTextProvider {
 
             // If we get to this point, we didn't show the form, so return the mandate from the form if it exists
             // 🙋‍♂️ Note: assumes mandates are SimpleMandateElement!
-            return form.getMandateText()
+            return PaymentMethodElementUtils.getMandateText(from: form)
         }
     }
 }
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/New Payment Method Screen/AddPaymentMethodViewController.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/New Payment Method Screen/AddPaymentMethodViewController.swift
index ca2f96519ee8..f5ac3419293c 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/New Payment Method Screen/AddPaymentMethodViewController.swift	
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/New Payment Method Screen/AddPaymentMethodViewController.swift	
@@ -206,7 +206,7 @@ class AddPaymentMethodViewController: UIViewController {
     }
 
     func clearTextFields() {
-        paymentMethodFormElement.clearTextFields()
+        PaymentMethodElementUtils.clearTextFields(in: paymentMethodFormElement)
     }
 }
 
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/PaymentSheetError.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/PaymentSheetError.swift
index 9ba0b987270b..600d31c86cc2 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/PaymentSheetError.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/PaymentSheetError.swift
@@ -14,7 +14,7 @@ import StripePayments
 ///
 /// Most errors do not originate from PaymentSheet itself; instead, they come from the Stripe API
 /// or other SDK components like STPPaymentHandler, PassKit (Apple Pay), etc.
-public enum PaymentSheetError: Error, LocalizedError {
+@frozen public enum PaymentSheetError: Error, LocalizedError {
 
     /// An unknown error.
     case unknown(debugDescription: String)
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Saved Payment Method Screen/SavedPaymentOptionsViewController.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Saved Payment Method Screen/SavedPaymentOptionsViewController.swift
index aa4312bd2724..ffdbf87cea6e 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Saved Payment Method Screen/SavedPaymentOptionsViewController.swift	
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Saved Payment Method Screen/SavedPaymentOptionsViewController.swift	
@@ -574,7 +574,7 @@ extension SavedPaymentOptionsViewController: UICollectionViewDataSource, UIColle
             )
         }
         updateMandateView()
-        cvcFormElement.clearTextFields()
+        PaymentMethodElementUtils.clearTextFields(in: cvcFormElement)
         updateFormElement()
         delegate?.didUpdateSelection(viewController: self, paymentMethodSelection: viewModel)
     }
diff --git a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/ViewControllers/PaymentMethodFormViewController.swift b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/ViewControllers/PaymentMethodFormViewController.swift
index b0214d5308ee..b316398e0449 100644
--- a/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/ViewControllers/PaymentMethodFormViewController.swift
+++ b/StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/ViewControllers/PaymentMethodFormViewController.swift
@@ -172,7 +172,7 @@ class PaymentMethodFormViewController: UIViewController {
 
     // MARK: - Helpers
     func clearTextFields() {
-        form.clearTextFields()
+        PaymentMethodElementUtils.clearTextFields(in: form)
     }
 
     /// Sets up the autocomplete button callback for any AddressSectionElement in the form
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/PaymentIntents/STPPaymentIntentEnums.swift b/StripePayments/StripePayments/Source/API Bindings/Models/PaymentIntents/STPPaymentIntentEnums.swift
index 24bf4d7ecc18..5e3fdbbc8db8 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/PaymentIntents/STPPaymentIntentEnums.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/PaymentIntents/STPPaymentIntentEnums.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Status types for an STPPaymentIntent
-@objc public enum STPPaymentIntentStatus: Int {
+@objc @frozen public enum STPPaymentIntentStatus: Int {
     /// Unknown status
     case unknown
     /// This PaymentIntent requires a PaymentMethod or Source
@@ -32,7 +32,7 @@ import Foundation
 /// Indicates how you intend to use the payment method that your customer provides after the current payment completes.
 /// If applicable, additional authentication may be performed to comply with regional legislation or network rules required to enable the usage of the same payment method for additional payments.
 /// - seealso: https://stripe.com/docs/api/payment_intents/object#payment_intent_object-setup_future_usage
-@objc public enum STPPaymentIntentSetupFutureUsage: Int {
+@objc @frozen public enum STPPaymentIntentSetupFutureUsage: Int {
     /// Unknown value.  Update your SDK, or use `allResponseFields` for custom handling.
     case unknown
     /// No value was provided.
@@ -72,7 +72,7 @@ import Foundation
 // MARK: - Deprecated
 /// Types of Actions from a `STPPaymentIntent`, when the payment intent
 /// status is `STPPaymentIntentStatusRequiresAction`.
-@objc public enum STPPaymentIntentActionType: Int {
+@objc @frozen public enum STPPaymentIntentActionType: Int {
     /// This is an unknown action, that's been added since the SDK
     /// was last updated.
     /// Update your SDK, or use the `nextAction.allResponseFields`
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/PaymentMethods/STPPaymentMethodAllowRedisplay.swift b/StripePayments/StripePayments/Source/API Bindings/Models/PaymentMethods/STPPaymentMethodAllowRedisplay.swift
index 8150d8d1eb17..165b48f2be22 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/PaymentMethods/STPPaymentMethodAllowRedisplay.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/PaymentMethods/STPPaymentMethodAllowRedisplay.swift	
@@ -6,7 +6,7 @@
 import Foundation
 
 /// Values for STPPaymentMethodAllowRedisplay
-@objc public enum STPPaymentMethodAllowRedisplay: Int {
+@objc @frozen public enum STPPaymentMethodAllowRedisplay: Int {
     /// This is the default value for payment methods where allow_redisplay wasn’t set.
     case unspecified
 
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/STPCardBrand.swift b/StripePayments/StripePayments/Source/API Bindings/Models/STPCardBrand.swift
index c5c87927cc99..3a9bce7cc582 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/STPCardBrand.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/STPCardBrand.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// The various card brands to which a payment card can belong.
-@objc public enum STPCardBrand: Int {
+@objc @frozen public enum STPCardBrand: Int {
     /// Visa card
     case visa
     /// American Express card
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/STPFPXBankBrand.swift b/StripePayments/StripePayments/Source/API Bindings/Models/STPFPXBankBrand.swift
index b5d23533639d..7cf41db51332 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/STPFPXBankBrand.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/STPFPXBankBrand.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// The various bank brands available for FPX payments.
-@objc public enum STPFPXBankBrand: Int {
+@objc @frozen public enum STPFPXBankBrand: Int {
     /// Maybank2U
     case maybank2U
     /// CIMB Clicks
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/STPFile.swift b/StripePayments/StripePayments/Source/API Bindings/Models/STPFile.swift
index d75997b3c7f2..94bcacfb78fe 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/STPFile.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/STPFile.swift	
@@ -12,7 +12,7 @@ import Foundation
 /// The purpose of the uploaded file.
 /// - seealso: https://stripe.com/docs/file-upload
 @objc
-public enum STPFilePurpose: Int {
+@frozen public enum STPFilePurpose: Int {
 
     // NOTE: If adding cases here, also add to `StripeFile.Purpose` or they will
     // not be encoded/decoded to/from the server.
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/STPToken.swift b/StripePayments/StripePayments/Source/API Bindings/Models/STPToken.swift
index b34454b319d0..784b5e3f662f 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/STPToken.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/STPToken.swift	
@@ -10,7 +10,7 @@ import Foundation
 
 /// Possible Token types
 @objc
-public enum STPTokenType: Int {
+@frozen public enum STPTokenType: Int {
     /// Account token type
     case account = 0
     /// Bank account token type
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/SetupIntents/STPSetupIntentEnums.swift b/StripePayments/StripePayments/Source/API Bindings/Models/SetupIntents/STPSetupIntentEnums.swift
index 012fd065bdb8..0c6a745a1993 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/SetupIntents/STPSetupIntentEnums.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/SetupIntents/STPSetupIntentEnums.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Status types for an STPSetupIntent
-@objc public enum STPSetupIntentStatus: Int {
+@objc @frozen public enum STPSetupIntentStatus: Int {
     /// Unknown status
     case unknown
     /// This SetupIntent requires a PaymentMethod
@@ -29,7 +29,7 @@ import Foundation
 
 /// Indicates how the payment method is intended to be used in the future.
 /// - seealso: https://stripe.com/docs/api/setup_intents/create#create_setup_intent-usage
-@objc public enum STPSetupIntentUsage: Int {
+@objc @frozen public enum STPSetupIntentUsage: Int {
     /// Unknown value.  Update your SDK, or use `allResponseFields` for custom handling.
     case unknown
     /// No value was provided.
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/Sources/STPSourceEnums.swift b/StripePayments/StripePayments/Source/API Bindings/Models/Sources/STPSourceEnums.swift
index 3726eb4215fd..620f1c95eabe 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/Sources/STPSourceEnums.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/Sources/STPSourceEnums.swift	
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Usage types for a Source
-@objc public enum STPSourceUsage: Int {
+@objc @frozen public enum STPSourceUsage: Int {
     /// The source can be reused.
     case reusable
     /// The source can only be used once.
@@ -19,7 +19,7 @@ import Foundation
 }
 
 /// Status types for a Source
-@objc public enum STPSourceStatus: Int {
+@objc @frozen public enum STPSourceStatus: Int {
     /// The source has been created and is awaiting customer action.
     case pending
     /// The source is ready to use. The customer action has been completed or the
@@ -40,7 +40,7 @@ import Foundation
 
 /// Types for a Source
 /// - seealso: https://stripe.com/docs/sources
-@objc public enum STPSourceType: Int {
+@objc @frozen public enum STPSourceType: Int {
     /// A card source. - seealso: https://stripe.com/docs/sources/cards
     case card
     /// An unknown type of source.
diff --git a/StripePayments/StripePayments/Source/API Bindings/Models/Sources/Types/STPCard.swift b/StripePayments/StripePayments/Source/API Bindings/Models/Sources/Types/STPCard.swift
index 34b96850153b..78074f703cb2 100644
--- a/StripePayments/StripePayments/Source/API Bindings/Models/Sources/Types/STPCard.swift	
+++ b/StripePayments/StripePayments/Source/API Bindings/Models/Sources/Types/STPCard.swift	
@@ -11,7 +11,7 @@ import UIKit
 
 /// The various funding sources for a payment card.
 @objc
-public enum STPCardFundingType: Int {
+@frozen public enum STPCardFundingType: Int {
     /// Debit card funding
     case debit
     /// Credit card funding
diff --git a/StripePayments/StripePayments/Source/Internal/Categories/STPAPIClient+PaymentsCore.swift b/StripePayments/StripePayments/Source/Internal/Categories/STPAPIClient+PaymentsCore.swift
index fb727c029850..48d3a7b1a147 100644
--- a/StripePayments/StripePayments/Source/Internal/Categories/STPAPIClient+PaymentsCore.swift
+++ b/StripePayments/StripePayments/Source/Internal/Categories/STPAPIClient+PaymentsCore.swift
@@ -31,7 +31,7 @@ extension STPAPIClient {
         )
         var newParams = params
         do {
-            newParams["client_attribution_metadata"] = try clientAttributionMetadata.encodeJSONDictionary()
+            newParams["client_attribution_metadata"] = try StripeJSONEncoder().encodeJSONDictionary(clientAttributionMetadata)
         } catch {
             stpAssertionFailure("Could not encode clientAttributionMetadata to JSON: \(error)")
         }
diff --git a/StripePayments/StripePayments/Source/PaymentHandler/STPPaymentHandler.swift b/StripePayments/StripePayments/Source/PaymentHandler/STPPaymentHandler.swift
index 2f2c33cd6351..daaccd1ab411 100644
--- a/StripePayments/StripePayments/Source/PaymentHandler/STPPaymentHandler.swift
+++ b/StripePayments/StripePayments/Source/PaymentHandler/STPPaymentHandler.swift
@@ -17,7 +17,7 @@ import Stripe3DS2
 #endif
 
 /// `STPPaymentHandlerActionStatus` represents the possible outcomes of requesting an action by `STPPaymentHandler`. An action could be confirming and/or handling the next action for a PaymentIntent.
-@objc public enum STPPaymentHandlerActionStatus: Int {
+@objc @frozen public enum STPPaymentHandlerActionStatus: Int {
     /// The action succeeded.
     case succeeded
     /// The action was cancelled by the cardholder/user.
@@ -27,7 +27,7 @@ import Stripe3DS2
 }
 
 /// Error codes generated by `STPPaymentHandler`
-@objc public enum STPPaymentHandlerErrorCode: Int {
+@objc @frozen public enum STPPaymentHandlerErrorCode: Int {
     /// Indicates that the action requires an authentication method not recognized or supported by the SDK.
     @objc(STPPaymentHandlerUnsupportedAuthenticationErrorCode)
     case unsupportedAuthenticationErrorCode