diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/IJsonSchemaValidationProperties.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/IJsonSchemaValidationProperties.java
index 8277a10ae17ab..0adc037028bae 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/IJsonSchemaValidationProperties.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/IJsonSchemaValidationProperties.java
@@ -111,8 +111,8 @@ public interface IJsonSchemaValidationProperties {
      *     - <code>categoryOneOf</code> is a parameter of class <code>GetAccountVideos_categoryOneOf_parameter</code>, a model parameter that correctly prefixed by its namespace: <code>org::openapitools::server::model::GetAccountVideos_categoryOneOf_parameter</code><br>
      *     - but that <code>GetAccountVideos_categoryOneOf_parameter</code> class is inside an <code>std::optional</code><br>
      *     <br>
-     *   Then a correct generation of that parameter can be (for C++) <code>const org::openapitools::server::model::std::optional<org::openapitools::server::model::GetAccountVideos_categoryOneOf_parameter> &categoryOneOf</code><br>
-     *   but using #isModel alone without #isOptional in mustache might produce <code>const org::openapitools::server::model::std::optional<org::openapitools::server::model::GetAccountVideos_categoryOneOf_parameter> &categoryOneOf</code> instead, that do not compile.
+     *   Then a correct generation of that parameter can be (for C++) <code>const std::optional<org::openapitools::server::model::GetAccountVideos_categoryOneOf_parameter> &categoryOneOf</code><br>
+         *   but using #isModel alone without #isOptional in mustache might produce <code>const org::openapitools::server::model::std::optional<org::openapitools::server::model::GetAccountVideos_categoryOneOf_parameter> &categoryOneOf</code> instead, that do not compile.
      */
     boolean getIsOptional();
     void setIsOptional(boolean isOptional);
diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
index b8c4e8b27475a..2e6f70491ec72 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
@@ -65,7 +65,7 @@ private:
     {{#allParams}}
     /// <param name="{{paramName}}">{{description}}{{^required}} (optional{{#defaultValue}}, default to {{.}}{{/defaultValue}}){{/required}}</param>
     {{/allParams}}
-    virtual void {{operationIdSnakeCase}}({{#allParams}}const {{#isModel}}{{modelNamespace}}::{{/isModel}}{{{dataType}}} &{{paramName}}{{^-last}}, {{/-last}}{{/allParams}}{{#hasParams}}, {{/hasParams}}Pistache::Http::ResponseWriter &response) = 0;
+    virtual void {{operationIdSnakeCase}}({{#allParams}}const {{#isModel}}{{^isOptional}}{{modelNamespace}}::{{/isOptional}}{{/isModel}}{{{dataType}}} &{{paramName}}{{^-last}}, {{/-last}}{{/allParams}}{{#hasParams}}, {{/hasParams}}Pistache::Http::ResponseWriter &response) = 0;
     {{/vendorExtensions.x-codegen-pistache-is-parsing-supported}}
     {{^vendorExtensions.x-codegen-pistache-is-parsing-supported}}
     virtual void {{operationIdSnakeCase}}(const Pistache::Rest::Request &request, Pistache::Http::ResponseWriter &response) = 0;
diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
index f6bc8972e9a3f..5b791c498590d 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
@@ -79,6 +79,23 @@ public:
     friend {{declspec}} void from_json(const nlohmann::json& j, {{classname}}& o);{{#vendorExtensions.x-is-string-enum-container}}{{#anyOf}}{{#-first}}
     friend {{declspec}} void to_json(nlohmann::json& j, const {{{this}}}& o);
     friend {{declspec}} void from_json(const nlohmann::json& j, {{{this}}}& o);{{/-first}}{{/anyOf}}{{/vendorExtensions.x-is-string-enum-container}}
+
+    {{#isEnum}}
+    /// <summary>
+    /// From enumerated value e{{classname}} to string value
+    /// </summary>
+    static std::string toStringValue(const {{classname}}::e{{classname}} &value) const;
+    static std::string toStringValue(const {{classname}} &value) const;
+    {{/isEnum}}
+
+    {{#isEnum}}
+    /// <summary>
+    /// From string value to enumerated value e{{classname}}
+    /// </summary>
+    static bool fromStringValue(const std::string &inStr, {{classname}}::e{{classname}} &value);
+    static bool fromStringValue(const std::string &inStr, {{classname}} &value);
+    {{/isEnum}}
+
 protected:
     {{#vars}}
     {{{dataType}}} m_{{name}};
diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-source.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-source.mustache
index ae6f06a4cf435..3e5e4fbfbacd2 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-source.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-source.mustache
@@ -181,6 +181,41 @@ void {{classname}}::setEnumValue({{{this}}}::e{{{this}}}  value)
     m_value.setValue(value);
 }{{/-first}}{{/anyOf}}{{/vendorExtensions.x-is-string-enum-container}}
 
+{{#isEnum}}
+/// <summary>
+/// From enumerated value eVideoPrivacySet to string value
+/// </summary>
+std::string {{classname}}::toStringValue(const {{classname}}::e{{classname}} &value)
+{
+    return "ukn";
+}
+
+std::string {{classname}}::toStringValue(const {{classname}} &value)
+{
+    return "ukn";
+}
+
+/// <summary>
+/// From string value to enumerated value e{{classname}}
+/// </summary>
+bool {{classname}}::fromStringValue(const std::string &inStr, {{classname}}::e{{classname}} &value)
+{
+    // TODO get value
+    {{classname}}::e{{classname}} dummy;
+    return true;
+    // TODO throw if invalid value
+}
+
+bool {{classname}}::fromStringValue(const std::string &inStr, {{classname}} &value)
+{
+    // TODO get value
+    {{classname}}::e{{classname}} dummy;
+    return true;
+    // TODO throw if invalid value
+}
+
+{{/isEnum}}
+
 } // namespace {{modelNamespace}}
 
 {{/model}}