diff --git a/modules/openapi-generator/src/main/resources/cpp-qt5-client/ServerConfiguration.mustache b/modules/openapi-generator/src/main/resources/cpp-qt5-client/ServerConfiguration.mustache
index 87bf899487c..d4bd3526316 100644
--- a/modules/openapi-generator/src/main/resources/cpp-qt5-client/ServerConfiguration.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-qt5-client/ServerConfiguration.mustache
@@ -7,6 +7,7 @@
 #include <QString>
 #include <QMap>
 #include <QRegularExpression>
+#include <stdexcept>
 #include "{{prefix}}ServerVariable.h"
 
 {{#cppNamespaceDeclarations}}
diff --git a/modules/openapi-generator/src/main/resources/cpp-qt5-client/api-body.mustache b/modules/openapi-generator/src/main/resources/cpp-qt5-client/api-body.mustache
index fb48260ace7..08ae9aa8ddb 100644
--- a/modules/openapi-generator/src/main/resources/cpp-qt5-client/api-body.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-qt5-client/api-body.mustache
@@ -227,10 +227,10 @@ void {{classname}}::{{nickname}}({{#allParams}}const {{{dataType}}} &{{paramName
     QByteArray bytes = doc.toJson();
     input.request_body.append(bytes);
 {{/isContainer}}{{^isContainer}}{{#isString}}
-    QString output({{paramName}});{{/isString}}{{#isByteArray}}QString output({{paramName}});{{/isByteArray}}{{^isString}}{{^isByteArray}}{{^isFile}}
-    QString output = {{paramName}}.asJson();{{/isFile}}{{/isByteArray}}{{/isString}}{{#isFile}}{{#hasConsumes}}input.headers.insert("Content-Type", {{#consumes}}{{^-first}}, {{/-first}}"{{mediaType}}"{{/consumes}});{{/hasConsumes}}
+    QByteArray output = {{paramName}}.toUtf8();{{/isString}}{{#isByteArray}}QByteArray output({{paramName}});{{/isByteArray}}{{^isString}}{{^isByteArray}}{{^isFile}}
+    QByteArray output = {{paramName}}.asJson().toUtf8();{{/isFile}}{{/isByteArray}}{{/isString}}{{#isFile}}{{#hasConsumes}}input.headers.insert("Content-Type", {{#consumes}}{{^-first}}, {{/-first}}"{{mediaType}}"{{/consumes}});{{/hasConsumes}}
     QByteArray output = {{paramName}}.asByteArray();{{/isFile}}
-    input.request_body.append(output.toUtf8());
+    input.request_body.append(output);
 {{/isContainer}}{{/bodyParams}}{{#headerParams}}
     if (!::{{cppNamespace}}::toStringValue({{paramName}}).isEmpty()) {
         input.headers.insert("{{baseName}}", ::{{cppNamespace}}::toStringValue({{paramName}}));
diff --git a/modules/openapi-generator/src/main/resources/cpp-restbed-server/model-source.mustache b/modules/openapi-generator/src/main/resources/cpp-restbed-server/model-source.mustache
index 06f161f2f07..9d56632b7fb 100644
--- a/modules/openapi-generator/src/main/resources/cpp-restbed-server/model-source.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-restbed-server/model-source.mustache
@@ -5,6 +5,7 @@
 
 #include <string>
 #include <sstream>
+#include <stdexcept>
 {{#hasEnums}}
 #include <algorithm>
 {{/hasEnums}}
diff --git a/samples/client/petstore/cpp-qt5/client/PFXPetApi.cpp b/samples/client/petstore/cpp-qt5/client/PFXPetApi.cpp
index 42c59efa8e9..14e5285627b 100644
--- a/samples/client/petstore/cpp-qt5/client/PFXPetApi.cpp
+++ b/samples/client/petstore/cpp-qt5/client/PFXPetApi.cpp
@@ -154,8 +154,8 @@ void PFXPetApi::addPet(const PFXPet &body) {
     worker->setWorkingDirectory(_workingDirectory);
     PFXHttpRequestInput input(fullPath, "POST");
 
-    QString output = body.asJson();
-    input.request_body.append(output.toUtf8());
+    QByteArray output = body.asJson().toUtf8();
+    input.request_body.append(output);
 
     foreach (QString key, this->defaultHeaders.keys()) { input.headers.insert(key, this->defaultHeaders.value(key)); }
 
@@ -458,8 +458,8 @@ void PFXPetApi::updatePet(const PFXPet &body) {
     worker->setWorkingDirectory(_workingDirectory);
     PFXHttpRequestInput input(fullPath, "PUT");
 
-    QString output = body.asJson();
-    input.request_body.append(output.toUtf8());
+    QByteArray output = body.asJson().toUtf8();
+    input.request_body.append(output);
 
     foreach (QString key, this->defaultHeaders.keys()) { input.headers.insert(key, this->defaultHeaders.value(key)); }
 
diff --git a/samples/client/petstore/cpp-qt5/client/PFXServerConfiguration.h b/samples/client/petstore/cpp-qt5/client/PFXServerConfiguration.h
index b619015428c..cc5273b8226 100644
--- a/samples/client/petstore/cpp-qt5/client/PFXServerConfiguration.h
+++ b/samples/client/petstore/cpp-qt5/client/PFXServerConfiguration.h
@@ -17,6 +17,7 @@
 #include <QString>
 #include <QMap>
 #include <QRegularExpression>
+#include <stdexcept>
 #include "PFXServerVariable.h"
 
 namespace test_namespace {
diff --git a/samples/client/petstore/cpp-qt5/client/PFXStoreApi.cpp b/samples/client/petstore/cpp-qt5/client/PFXStoreApi.cpp
index 1dbc49ff86c..211e318b688 100644
--- a/samples/client/petstore/cpp-qt5/client/PFXStoreApi.cpp
+++ b/samples/client/petstore/cpp-qt5/client/PFXStoreApi.cpp
@@ -277,8 +277,8 @@ void PFXStoreApi::placeOrder(const PFXOrder &body) {
     worker->setWorkingDirectory(_workingDirectory);
     PFXHttpRequestInput input(fullPath, "POST");
 
-    QString output = body.asJson();
-    input.request_body.append(output.toUtf8());
+    QByteArray output = body.asJson().toUtf8();
+    input.request_body.append(output);
 
     foreach (QString key, this->defaultHeaders.keys()) { input.headers.insert(key, this->defaultHeaders.value(key)); }
 
diff --git a/samples/client/petstore/cpp-qt5/client/PFXUserApi.cpp b/samples/client/petstore/cpp-qt5/client/PFXUserApi.cpp
index aef910a0af9..389e99f83d2 100644
--- a/samples/client/petstore/cpp-qt5/client/PFXUserApi.cpp
+++ b/samples/client/petstore/cpp-qt5/client/PFXUserApi.cpp
@@ -154,8 +154,8 @@ void PFXUserApi::createUser(const PFXUser &body) {
     worker->setWorkingDirectory(_workingDirectory);
     PFXHttpRequestInput input(fullPath, "POST");
 
-    QString output = body.asJson();
-    input.request_body.append(output.toUtf8());
+    QByteArray output = body.asJson().toUtf8();
+    input.request_body.append(output);
 
     foreach (QString key, this->defaultHeaders.keys()) { input.headers.insert(key, this->defaultHeaders.value(key)); }
 
@@ -455,8 +455,8 @@ void PFXUserApi::updateUser(const QString &username, const PFXUser &body) {
     worker->setWorkingDirectory(_workingDirectory);
     PFXHttpRequestInput input(fullPath, "PUT");
 
-    QString output = body.asJson();
-    input.request_body.append(output.toUtf8());
+    QByteArray output = body.asJson().toUtf8();
+    input.request_body.append(output);
 
     foreach (QString key, this->defaultHeaders.keys()) { input.headers.insert(key, this->defaultHeaders.value(key)); }