diff --git a/src/LocalizationData.cpp b/src/LocalizationData.cpp
index a39200f..0a5ae25 100644
--- a/src/LocalizationData.cpp
+++ b/src/LocalizationData.cpp
@@ -78,37 +78,44 @@ void LocalizationData::WriteToFile(const std::filesystem::path& path) {
         tempFilesPositions[file.first] = p1;
     }
     outFile << "ENDDATA" << std::endl;
+
+    size_t numberGlobal = 0;
     // actual localization
     for (const auto& file : _globalFiles) {
         auto pos = outFile.tellp();
         for (const auto& kv : file.second.GetMap()) {
             outFile << kv.first << "|" << kv.second << std::endl;
+            numberGlobal++;
         }
         auto end = outFile.tellp();
         auto length = end - pos;
         auto data = globalFilesPositions[file.first];
         outFile.seekp(data);
-        outFile << std::setfill ('0') << std::setw(4) << std::hex << pos;
+        outFile << std::setfill('0') << std::setw(4) << std::hex << pos;
         outFile << "~";
-        outFile << std::setfill ('0') << std::setw(4) << std::hex << length;
+        outFile << std::setfill('0') << std::setw(4) << std::hex << length;
         outFile.seekp(end);
     }
+
+    size_t numberTemp = 0;
     for (const auto& file : _tempFiles) {
         auto pos = outFile.tellp();
         for (const auto& kv : file.second.GetMap()) {
             outFile << kv.first << "|" << kv.second << std::endl;
+            numberTemp++;
         }
         auto end = outFile.tellp();
         auto length = end - pos;
         auto data = tempFilesPositions[file.first];
         outFile.seekp(data);
-        outFile << std::setfill ('0') << std::setw(4) << std::hex << pos;
+        outFile << std::setfill('0') << std::setw(4) << std::hex << pos;
         outFile << "~";
-        outFile << std::setfill ('0') << std::setw(4) << std::hex << length;
+        outFile << std::setfill('0') << std::setw(4) << std::hex << length;
         outFile.seekp(end);
     }
 
     outFile.close();
 
-    std::cout << "Wrote language file to " << path << std::endl;
+    std::cout << "Wrote language file to " << path << ". Wrote " << numberGlobal << " global keys and " << numberTemp
+              << " temp keys." << std::endl;
 }
diff --git a/src/LocalizationFile.cpp b/src/LocalizationFile.cpp
index 134182a..13a97f8 100644
--- a/src/LocalizationFile.cpp
+++ b/src/LocalizationFile.cpp
@@ -1,6 +1,16 @@
 #include "LocalizationFile.hpp"
 #include <fstream>
 #include <iostream>
+#include <regex>
+
+const std::regex keyChecker = std::regex("[^a-z0-9_]+");
+
+static bool IsKeyValid(const std::string_view & key){
+    if (std::regex_search(key.begin(), key.end(), keyChecker)){
+        return false;
+    }
+    return true;
+}
 
 void LocalizationFile::LoadFile(const std::filesystem::path& path) {
     if (!std::filesystem::exists(path)) {
@@ -33,6 +43,9 @@ void LocalizationFile::LoadFile(const std::filesystem::path& path) {
         std::getline(linestream, value, sep);
         if (key.empty())
             continue;
+        if (!IsKeyValid(key)){
+            std::cout << "Key not valid: '" << key << "'. Skipping key." << std::endl;
+        }
         _map[key] = value;
     }
     file.close();