diff --git a/benchmark/static_reflect/citm_catalog_benchmark/benchmark_serialization_citm_catalog.cpp b/benchmark/static_reflect/citm_catalog_benchmark/benchmark_serialization_citm_catalog.cpp
index 1570c27b6..16b88d894 100644
--- a/benchmark/static_reflect/citm_catalog_benchmark/benchmark_serialization_citm_catalog.cpp
+++ b/benchmark/static_reflect/citm_catalog_benchmark/benchmark_serialization_citm_catalog.cpp
@@ -40,16 +40,13 @@ void bench_reflect_cpp(CitmCatalog &data) {
 
 void bench_rust(serde_benchmark::CitmCatalog *data) {
   serde_benchmark::set_citm_data(data);
-  char * output = serde_benchmark::serialize_citm_to_string();
-  size_t output_volume = strlen(output);
+  size_t output_volume = serde_benchmark::serialize_citm_to_string();
   printf("# output volume: %zu bytes\n", output_volume);
-  serde_benchmark::free_str(output);
 
   volatile size_t measured_volume = 0;
   pretty_print(1, output_volume, "bench_rust",
                bench([&measured_volume, &output_volume]() {
-                 char * output = serde_benchmark::serialize_citm_to_string();
-                 serde_benchmark::free_str(output);
+                 measured_volume = serde_benchmark::serialize_citm_to_string();
                }));
 }
 #endif // SIMDJSON_RUST_VERSION
diff --git a/benchmark/static_reflect/serde-benchmark/lib.rs b/benchmark/static_reflect/serde-benchmark/lib.rs
index 969e6d3ed..4a3fe55f6 100644
--- a/benchmark/static_reflect/serde-benchmark/lib.rs
+++ b/benchmark/static_reflect/serde-benchmark/lib.rs
@@ -38,7 +38,6 @@ pub struct Status {
 pub struct TwitterData {
     statuses: Vec<Status>,
 }
-
 static mut TWITTER_DATA: *mut TwitterData = std::ptr::null_mut();
 
 #[no_mangle]
@@ -56,13 +55,12 @@ pub unsafe extern "C" fn set_twitter_data(raw: *mut TwitterData) {
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn serialize_twitter_to_string() -> *const c_char {
+pub unsafe extern "C" fn serialize_twitter_to_string() -> usize {
     if TWITTER_DATA.is_null() {
-        return std::ptr::null();
+        return 0;
     }
     let data = &*TWITTER_DATA;
-    let serialized = serde_json::to_string(data).unwrap();
-    std::ffi::CString::new(serialized).unwrap().into_raw() as *const c_char
+    serde_json::to_string(data).unwrap().len()
 }
 
 #[no_mangle]
@@ -214,13 +212,12 @@ pub unsafe extern "C" fn set_citm_data(raw: *mut CitmCatalog) {
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn serialize_citm_to_string() -> *mut c_char {
+pub unsafe extern "C" fn serialize_citm_to_string() -> usize {
     if CITM_DATA.is_null() {
-        return std::ptr::null_mut();
+        return 0;
     }
     let data = &*CITM_DATA;
-    let serialized = serde_json::to_string(data).unwrap();
-    std::ffi::CString::new(serialized).unwrap().into_raw()
+    return serde_json::to_string(data).unwrap().len();
 }
 
 /// Frees the CitmCatalog pointer.
diff --git a/benchmark/static_reflect/serde-benchmark/serde_benchmark.h b/benchmark/static_reflect/serde-benchmark/serde_benchmark.h
index c121c86e5..3dded524f 100644
--- a/benchmark/static_reflect/serde-benchmark/serde_benchmark.h
+++ b/benchmark/static_reflect/serde-benchmark/serde_benchmark.h
@@ -36,7 +36,7 @@ TwitterData *twitter_from_str(const char *raw_input, size_t raw_input_length);
 
 void set_twitter_data(TwitterData *raw);
 
-const char *serialize_twitter_to_string();
+size_t serialize_twitter_to_string();
 
 void free_twitter(TwitterData *raw);
 
@@ -47,7 +47,7 @@ CitmCatalog *citm_from_str(const char *raw_input, uintptr_t raw_input_length);
 
 void set_citm_data(CitmCatalog *raw);
 
-char *serialize_citm_to_string();
+size_t serialize_citm_to_string();
 
 /// Frees the CitmCatalog pointer.
 void free_citm(CitmCatalog *raw_catalog);
diff --git a/benchmark/static_reflect/twitter_benchmark/benchmark_serialization_twitter.cpp b/benchmark/static_reflect/twitter_benchmark/benchmark_serialization_twitter.cpp
index 87685c8bd..98e8c6c6d 100644
--- a/benchmark/static_reflect/twitter_benchmark/benchmark_serialization_twitter.cpp
+++ b/benchmark/static_reflect/twitter_benchmark/benchmark_serialization_twitter.cpp
@@ -40,16 +40,13 @@ void bench_reflect_cpp(TwitterData &data) {
 
 void bench_rust(serde_benchmark::TwitterData *data) {
   serde_benchmark::set_twitter_data(data);
-  const char * output = serde_benchmark::serialize_twitter_to_string();
-  size_t output_volume = strlen(output);
+  size_t output_volume = serde_benchmark::serialize_twitter_to_string();
   printf("# output volume: %zu bytes\n", output_volume);
-  serde_benchmark::free_string(output);
 
   volatile size_t measured_volume = 0;
   pretty_print(1, output_volume, "bench_rust",
                bench([&measured_volume, &output_volume]() {
-                 const char * output = serde_benchmark::serialize_twitter_to_string();
-                 serde_benchmark::free_string(output);
+                 measured_volume = serde_benchmark::serialize_twitter_to_string();
                }));
 }
 #endif