diff --git a/headers/enum.hpp/enum.hpp b/headers/enum.hpp/enum.hpp
index 40b8731..f3bc598 100644
--- a/headers/enum.hpp/enum.hpp
+++ b/headers/enum.hpp/enum.hpp
@@ -10,6 +10,12 @@
 #include <string_view>
 #include <type_traits>
 
+namespace enum_hpp
+{
+    constexpr std::size_t invalid_index = std::size_t(-1);
+    constexpr std::string_view empty_string = std::string_view();
+}
+
 namespace enum_hpp::detail
 {
     template < typename Enum >
@@ -124,6 +130,12 @@ namespace enum_hpp::detail
             }\
             return std::nullopt;\
         }\
+        static constexpr std::string_view to_string_or_empty(Enum e) noexcept {\
+            if ( auto s = to_string(e) ) {\
+                return *s;\
+            }\
+            return ::enum_hpp::empty_string;\
+        }\
         \
         static constexpr std::optional<Enum> from_string(std::string_view name) noexcept {\
             for ( std::size_t i = 0; i < size; ++i) {\
@@ -143,6 +155,13 @@ namespace enum_hpp::detail
             return std::nullopt;\
         }\
         \
+        static constexpr std::size_t to_index_or_invalid(Enum e) noexcept {\
+            if ( auto i = to_index(e) ) {\
+                return *i;\
+            }\
+            return ::enum_hpp::invalid_index;\
+        }\
+        \
         static constexpr std::optional<Enum> from_index(std::size_t index) noexcept {\
             if ( index < size ) {\
                 return values[index];\
diff --git a/untests/enum_tests.cpp b/untests/enum_tests.cpp
index 348693e..f63d48f 100644
--- a/untests/enum_tests.cpp
+++ b/untests/enum_tests.cpp
@@ -133,19 +133,36 @@ TEST_CASE("enum") {
             STATIC_REQUIRE(sn::color_traits::to_string(sn::color::red) == "red");
             STATIC_REQUIRE(sn::color_traits::to_string(sn::color::green) == "green");
             STATIC_REQUIRE(sn::color_traits::to_string(sn::color::blue) == "blue");
+
+            STATIC_REQUIRE(sn::color_traits::to_string_or_empty(sn::color::red) == "red");
+            STATIC_REQUIRE(sn::color_traits::to_string_or_empty(sn::color::green) == "green");
+            STATIC_REQUIRE(sn::color_traits::to_string_or_empty(sn::color::blue) == "blue");
+
             STATIC_REQUIRE_FALSE(sn::color_traits::to_string(sn::color(42)));
+            STATIC_REQUIRE(sn::color_traits::to_string_or_empty(sn::color(42)) == "");
         }
         {
             STATIC_REQUIRE(sn::render::mask_traits::to_string(sn::render::mask::none) == "none");
             STATIC_REQUIRE(sn::render::mask_traits::to_string(sn::render::mask::color) == "color");
             STATIC_REQUIRE(sn::render::mask_traits::to_string(sn::render::mask::alpha) == "alpha");
             STATIC_REQUIRE(sn::render::mask_traits::to_string(sn::render::mask::all) == "all");
+
+            STATIC_REQUIRE(sn::render::mask_traits::to_string_or_empty(sn::render::mask::none) == "none");
+            STATIC_REQUIRE(sn::render::mask_traits::to_string_or_empty(sn::render::mask::color) == "color");
+            STATIC_REQUIRE(sn::render::mask_traits::to_string_or_empty(sn::render::mask::alpha) == "alpha");
+            STATIC_REQUIRE(sn::render::mask_traits::to_string_or_empty(sn::render::mask::all) == "all");
         }
         {
             STATIC_REQUIRE(sn::numbers_traits::to_string(sn::_0) == "_0");
             STATIC_REQUIRE(sn::numbers_traits::to_string(sn::_180) == "_180");
             STATIC_REQUIRE(sn::numbers_traits::to_string(sn::_240) == "_240");
+
+            STATIC_REQUIRE(sn::numbers_traits::to_string_or_empty(sn::_0) == "_0");
+            STATIC_REQUIRE(sn::numbers_traits::to_string_or_empty(sn::_180) == "_180");
+            STATIC_REQUIRE(sn::numbers_traits::to_string_or_empty(sn::_240) == "_240");
+
             STATIC_REQUIRE_FALSE(sn::numbers_traits::to_string(sn::numbers(100500)));
+            STATIC_REQUIRE(sn::numbers_traits::to_string_or_empty(sn::numbers(100500)) == "");
         }
     }
 
@@ -175,19 +192,36 @@ TEST_CASE("enum") {
             STATIC_REQUIRE(sn::color_traits::to_index(sn::color::red) == 0u);
             STATIC_REQUIRE(sn::color_traits::to_index(sn::color::green) == 1u);
             STATIC_REQUIRE(sn::color_traits::to_index(sn::color::blue) == 2u);
+
+            STATIC_REQUIRE(sn::color_traits::to_index_or_invalid(sn::color::red) == 0u);
+            STATIC_REQUIRE(sn::color_traits::to_index_or_invalid(sn::color::green) == 1u);
+            STATIC_REQUIRE(sn::color_traits::to_index_or_invalid(sn::color::blue) == 2u);
+
             STATIC_REQUIRE_FALSE(sn::color_traits::to_index(sn::color(42)));
+            STATIC_REQUIRE(sn::color_traits::to_index_or_invalid(sn::color(42)) == enum_hpp::invalid_index);
         }
         {
             STATIC_REQUIRE(sn::render::mask_traits::to_index(sn::render::mask::none) == 0u);
             STATIC_REQUIRE(sn::render::mask_traits::to_index(sn::render::mask::color) == 1u);
             STATIC_REQUIRE(sn::render::mask_traits::to_index(sn::render::mask::alpha) == 2u);
             STATIC_REQUIRE(sn::render::mask_traits::to_index(sn::render::mask::all) == 3u);
+
+            STATIC_REQUIRE(sn::render::mask_traits::to_index_or_invalid(sn::render::mask::none) == 0u);
+            STATIC_REQUIRE(sn::render::mask_traits::to_index_or_invalid(sn::render::mask::color) == 1u);
+            STATIC_REQUIRE(sn::render::mask_traits::to_index_or_invalid(sn::render::mask::alpha) == 2u);
+            STATIC_REQUIRE(sn::render::mask_traits::to_index_or_invalid(sn::render::mask::all) == 3u);
         }
         {
             STATIC_REQUIRE(sn::numbers_traits::to_index(sn::_0) == 0u);
             STATIC_REQUIRE(sn::numbers_traits::to_index(sn::_180) == 180u);
             STATIC_REQUIRE(sn::numbers_traits::to_index(sn::_240) == 240u);
+
+            STATIC_REQUIRE(sn::numbers_traits::to_index_or_invalid(sn::_0) == 0u);
+            STATIC_REQUIRE(sn::numbers_traits::to_index_or_invalid(sn::_180) == 180u);
+            STATIC_REQUIRE(sn::numbers_traits::to_index_or_invalid(sn::_240) == 240u);
+
             STATIC_REQUIRE_FALSE(sn::numbers_traits::to_index(sn::numbers(100500)));
+            STATIC_REQUIRE(sn::numbers_traits::to_index_or_invalid(sn::numbers(100500)) == enum_hpp::invalid_index);
         }
     }