diff --git a/include/io1/money.hpp b/include/io1/money.hpp
index 59ecaf1..cbebfd3 100644
--- a/include/io1/money.hpp
+++ b/include/io1/money.hpp
@@ -15,14 +15,6 @@
 #include <string>
 #include <type_traits>
 
-namespace io1
-{
-  class money;
-}
-
-template <char... STR>
-constexpr io1::money operator""_money(void) noexcept;
-
 namespace io1
 {
   class money
@@ -49,9 +41,6 @@ namespace io1
     template <std::floating_point T>
     explicit constexpr money(T amount) noexcept = delete;
 
-    template <char... STR>
-    friend constexpr money(::operator""_money)(void) noexcept;
-
     [[nodiscard]] constexpr value_type const & data(void) const noexcept { return amount_; }
 
     [[nodiscard]] constexpr money operator++(int) noexcept { return money{amount_++}; }
@@ -120,7 +109,6 @@ namespace io1
     };
 
   private:
-    struct StringLitteralDecoder;
     struct PutMoney;
     struct GetMoney;
 
@@ -203,52 +191,55 @@ namespace io1
   }
 
   // Helper structure to build a io1::Money object from a user-defined string litteral
-  struct money::StringLitteralDecoder
+  namespace detail
   {
-  public:
-    template <char... STR>
-    [[nodiscard]] constexpr static money apply(void) noexcept
+    struct StringLitteralDecoder
     {
-      return money{parse_mantissa<0, STR...>()};
-    }
+    public:
+      template <char... STR>
+      [[nodiscard]] constexpr static money apply(void) noexcept
+      {
+        return money{parse_mantissa<0, STR...>()};
+      }
 
-  private:
-    template <value_type CURRENT_MANTISSA, char DIGIT>
-    [[nodiscard]] constexpr static value_type parse_digit(void) noexcept
-    {
-      static_assert('0' <= DIGIT && '9' >= DIGIT, "Unexpected digit!");
+    private:
+      template <money::value_type CURRENT_MANTISSA, char DIGIT>
+      [[nodiscard]] constexpr static money::value_type parse_digit(void) noexcept
+      {
+        static_assert('0' <= DIGIT && '9' >= DIGIT, "Unexpected digit!");
 
-      constexpr auto d = static_cast<value_type>(DIGIT - '0');
-      constexpr auto ten = static_cast<value_type>(10);
+        constexpr auto d = static_cast<money::value_type>(DIGIT - '0');
+        constexpr auto ten = static_cast<money::value_type>(10);
 
-      static_assert(CURRENT_MANTISSA >= 0, "Parsing a raw user-defined litteral.");
-      static_assert((std::numeric_limits<value_type>::max() - d) / ten >= CURRENT_MANTISSA,
-                    "Number not representable by io1::Money");
+        static_assert(CURRENT_MANTISSA >= 0, "Parsing a raw user-defined litteral.");
+        static_assert((std::numeric_limits<money::value_type>::max() - d) / ten >= CURRENT_MANTISSA,
+                      "Number not representable by io1::Money");
 
-      return ten * CURRENT_MANTISSA + d;
-    }
+        return ten * CURRENT_MANTISSA + d;
+      }
 
-    template <char DIGIT>
-    [[nodiscard]] constexpr static bool not_a_digit(void) noexcept
-    {
-      return (DIGIT == '.' || DIGIT == '\'');
-    }
+      template <char DIGIT>
+      [[nodiscard]] constexpr static bool not_a_digit(void) noexcept
+      {
+        return (DIGIT == '.' || DIGIT == '\'');
+      }
 
-    template <value_type CURRENT_MANTISSA, char DIGIT, char... STR>
-    constexpr static value_type parse_mantissa(void) noexcept
-    {
-      constexpr auto new_mantissa = []()
+      template <money::value_type CURRENT_MANTISSA, char DIGIT, char... STR>
+      constexpr static money::value_type parse_mantissa(void) noexcept
       {
-        if constexpr (not_a_digit<DIGIT>()) return CURRENT_MANTISSA;
+        constexpr auto new_mantissa = []()
+        {
+          if constexpr (not_a_digit<DIGIT>()) return CURRENT_MANTISSA;
+          else
+            return parse_digit<CURRENT_MANTISSA, DIGIT>();
+        }();
+
+        if constexpr (0 < sizeof...(STR)) return parse_mantissa<new_mantissa, STR...>();
         else
-          return parse_digit<CURRENT_MANTISSA, DIGIT>();
-      }();
-
-      if constexpr (0 < sizeof...(STR)) return parse_mantissa<new_mantissa, STR...>();
-      else
-        return new_mantissa;
-    }
-  };
+          return new_mantissa;
+      }
+    };
+  } // namespace detail
 
   inline std::ostream & operator<<(std::ostream & stream, io1::money m) noexcept
   {
@@ -344,14 +335,16 @@ namespace io1
     return {.quot = money(result.quot), .rem = money(result.rem)};
   }
 
+  inline namespace literals
+  {
+    template <char... STR>
+    constexpr io1::money operator""_money(void) noexcept
+    {
+      return io1::detail::StringLitteralDecoder::apply<STR...>();
+    }
+  } // namespace literals
 } // namespace io1
 
-template <char... STR>
-constexpr io1::money operator""_money(void) noexcept
-{
-  return io1::money::StringLitteralDecoder::apply<STR...>();
-}
-
 template <class CharT>
 struct std::formatter<io1::money, CharT>
 {
diff --git a/test/test_money.cpp b/test/test_money.cpp
index bb3cc02..993d4e3 100644
--- a/test/test_money.cpp
+++ b/test/test_money.cpp
@@ -9,6 +9,8 @@
 #define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
 #include <doctest/doctest.h>
 
+using namespace io1::literals;
+
 TEST_CASE("Value bounds")
 {
   [[maybe_unused]] constexpr auto max = 9'223'372'036'854'775'807_money;
diff --git a/test/tutorial.cpp b/test/tutorial.cpp
index 32a9212..351f9d6 100644
--- a/test/tutorial.cpp
+++ b/test/tutorial.cpp
@@ -6,6 +6,8 @@
 #include <sstream>
 #include <vector>
 
+using namespace io1::literals;
+
 class american_moneypunct_facet : public std::moneypunct<char, false>
 {
 private: