diff --git a/include/Barcode/BarcodeFactory.h b/include/Barcode/BarcodeFactory.h
index 75becd9..4d94915 100644
--- a/include/Barcode/BarcodeFactory.h
+++ b/include/Barcode/BarcodeFactory.h
@@ -19,5 +19,5 @@
 
 class BarcodeFactory {
 public:
-    static std::unique_ptr<IBarcodeGenerator> create(const std::string type);
+  static std::unique_ptr<IBarcodeGenerator> create(const std::string type);
 };
diff --git a/src/main.cpp b/src/main.cpp
index a37b2c1..842321c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -6,6 +6,7 @@
 #include <ZXing/CharacterSet.h>
 #include <ZXing/MultiFormatWriter.h>
 #include <memory>
+#include <stdexcept>
 #include <string>
 #include <utility>
 
@@ -18,16 +19,24 @@ int main() {
     auto margin = req.url_params.get("margin");
     auto size = req.url_params.get("size");
     std::unique_ptr<IBarcodeGenerator> generator = BarcodeFactory::create(type);
-    std::string matrix =
-        generator->generate(text, std::stoi(margin), std::stoi(size));
 
+    std::string matrix;
     crow::response resp;
-    resp.code = 200;
-    resp.add_header("Content-Type", "image/svg+xml");
-    resp.body = std::move(matrix);
+    try {
+      matrix = generator->generate(text, std::stoi(margin), std::stoi(size));
+
+      resp.code = 200;
+      resp.add_header("Content-Type", "image/svg+xml");
+      resp.body = std::move(matrix);
+    } catch (const std::invalid_argument &ex) {
+      std::cerr << ex.what() << std::endl;
+      resp.code = 400;
+      resp.add_header("Content-Type", "text/html");
+      resp.body = std::move(matrix);
+    }
 
     return resp;
   });
 
-  app.port(80).multithreaded().run();
+  app.port(8080).multithreaded().run();
 }