diff --git a/modules/openapi-generator/src/main/resources/swift5/Models.mustache b/modules/openapi-generator/src/main/resources/swift5/Models.mustache
index 7890f011339..dc69d0c0b45 100644
--- a/modules/openapi-generator/src/main/resources/swift5/Models.mustache
+++ b/modules/openapi-generator/src/main/resources/swift5/Models.mustache
@@ -35,14 +35,14 @@ extension CaseIterableDefaultsLast {
 
 /// A flexible type that can be encoded (`.encodeNull` or `.encodeValue`)
 /// or not encoded (`.encodeNothing`). Intended for request payloads.
-public enum NullEncodable<Wrapped: Hashable>: Hashable {
+{{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} enum NullEncodable<Wrapped: Hashable>: Hashable {
     case encodeNothing
     case encodeNull
     case encodeValue(Wrapped)
 }
 
 extension NullEncodable: Codable where Wrapped: Codable {
-    public init(from decoder: Decoder) throws {
+    {{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} init(from decoder: Decoder) throws {
         let container = try decoder.singleValueContainer()
         if let value = try? container.decode(Wrapped.self) {
             self = .encodeValue(value)
@@ -53,7 +53,7 @@ extension NullEncodable: Codable where Wrapped: Codable {
         }
     }
 
-    public func encode(to encoder: Encoder) throws {
+    {{#nonPublicApi}}internal{{/nonPublicApi}}{{^nonPublicApi}}public{{/nonPublicApi}} func encode(to encoder: Encoder) throws {
         var container = encoder.singleValueContainer()
         switch self {
         case .encodeNothing: return
diff --git a/samples/client/petstore/swift5/nonPublicApi/PetstoreClient/Classes/OpenAPIs/Models.swift b/samples/client/petstore/swift5/nonPublicApi/PetstoreClient/Classes/OpenAPIs/Models.swift
index 171ced2359b..356d9c7454e 100644
--- a/samples/client/petstore/swift5/nonPublicApi/PetstoreClient/Classes/OpenAPIs/Models.swift
+++ b/samples/client/petstore/swift5/nonPublicApi/PetstoreClient/Classes/OpenAPIs/Models.swift
@@ -34,14 +34,14 @@ extension CaseIterableDefaultsLast {
 
 /// A flexible type that can be encoded (`.encodeNull` or `.encodeValue`)
 /// or not encoded (`.encodeNothing`). Intended for request payloads.
-public enum NullEncodable<Wrapped: Hashable>: Hashable {
+internal enum NullEncodable<Wrapped: Hashable>: Hashable {
     case encodeNothing
     case encodeNull
     case encodeValue(Wrapped)
 }
 
 extension NullEncodable: Codable where Wrapped: Codable {
-    public init(from decoder: Decoder) throws {
+    internal init(from decoder: Decoder) throws {
         let container = try decoder.singleValueContainer()
         if let value = try? container.decode(Wrapped.self) {
             self = .encodeValue(value)
@@ -52,7 +52,7 @@ extension NullEncodable: Codable where Wrapped: Codable {
         }
     }
 
-    public func encode(to encoder: Encoder) throws {
+    internal func encode(to encoder: Encoder) throws {
         var container = encoder.singleValueContainer()
         switch self {
         case .encodeNothing: return