diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 3790ce2..b95cbb5 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -11,7 +11,7 @@ set(KLSK_CORE_SRC
     all_cases/internal/all_cases.cc
 
 #    common_code/internal/common_code.cc
-    common_code/internal/serialize.cc
+#    common_code/internal/serialize.cc
 #    common_code/internal/mirror.cc
 
 #    raw_code/internal/raw_code.cc
diff --git a/src/core/benchmark/common_code.cc b/src/core/benchmark/common_code.cc
index ae7b623..d83140d 100644
--- a/src/core/benchmark/common_code.cc
+++ b/src/core/benchmark/common_code.cc
@@ -138,14 +138,14 @@ static void CommonCodeHorizontalMirror(benchmark::State &state) {
 
 // BENCHMARK(CommonCodeCheck)->Range(8, 256);
 
-// BENCHMARK(CommonCodeSerialize)->Range(8, 256);
-// BENCHMARK(CommonCodeDeserialize)->Range(8, 256);
-// BENCHMARK(CommonCodeSerializeShorten)->Range(8, 256);
-// BENCHMARK(CommonCodeDeserializeShorten)->Range(8, 256);
+BENCHMARK(CommonCodeSerialize)->Range(16, 1024);
+BENCHMARK(CommonCodeDeserialize)->Range(16, 1024);
+BENCHMARK(CommonCodeSerializeShorten)->Range(16, 1024);
+BENCHMARK(CommonCodeDeserializeShorten)->Range(16, 1024);
 
 // BENCHMARK(CommonCodeCheckMirror)->Range(64, 1024);
 
-BENCHMARK(CommonCodeVerticalMirror)->Range(8, 256);
-BENCHMARK(CommonCodeHorizontalMirror)->Range(8, 256);
+// BENCHMARK(CommonCodeVerticalMirror)->Range(8, 256);
+// BENCHMARK(CommonCodeHorizontalMirror)->Range(8, 256);
 
 BENCHMARK_MAIN();
diff --git a/src/core/common_code/common_code.h b/src/core/common_code/common_code.h
index 9f5c083..213833a 100644
--- a/src/core/common_code/common_code.h
+++ b/src/core/common_code/common_code.h
@@ -199,6 +199,7 @@ static_assert(std::is_trivially_copyable_v<CommonCode>);
 } // namespace klotski::codec
 
 #include "internal/common_code.inl"
+#include "internal/serialize.inl"
 #include "internal/mirror.inl"
 #include "internal/check.inl"
 
diff --git a/src/core/common_code/internal/serialize.cc b/src/core/common_code/internal/serialize.inl
similarity index 91%
rename from src/core/common_code/internal/serialize.cc
rename to src/core/common_code/internal/serialize.inl
index 63315b1..65ad95b 100644
--- a/src/core/common_code/internal/serialize.cc
+++ b/src/core/common_code/internal/serialize.inl
@@ -1,4 +1,4 @@
-#include "common_code/common_code.h"
+#pragma once
 
 namespace klotski::codec {
 
@@ -53,7 +53,7 @@ constexpr auto CONVERT_TABLE = std::to_array<char>({
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 });
 
-std::string CommonCode::string_encode(uint64_t common_code) {
+inline std::string CommonCode::string_encode(uint64_t common_code) {
     char code_str[9];
     for (int i = 0; i < 9; ++i) {
         code_str[8 - i] = to_hex_char(common_code & 0b1111);
@@ -62,7 +62,7 @@ std::string CommonCode::string_encode(uint64_t common_code) {
     return std::string{code_str, code_str + 9};
 }
 
-std::string CommonCode::string_encode_shorten(const uint64_t common_code) {
+inline std::string CommonCode::string_encode_shorten(const uint64_t common_code) {
     if (common_code == 0) {
         return "0"; // special case
     }
@@ -71,7 +71,7 @@ std::string CommonCode::string_encode_shorten(const uint64_t common_code) {
     return code;
 }
 
-std::optional<uint64_t> CommonCode::string_decode(const std::string_view common_code) {
+inline std::optional<uint64_t> CommonCode::string_decode(const std::string_view common_code) {
     if (common_code.length() > 9 || common_code.empty()) {
         return std::nullopt; // invalid string length
     }