Optimize server connection handling and JSON serialization

Refactored server.rs to reduce per-request allocations by introducing a connection-level service and custom future, and enabled TCP_NODELAY for lower latency. Improved JSON serialization in json.rs to use simd-json when available, and updated dependencies to include socket2. Updated README performance numbers and added a test JSON body for benchmarks.

Author: Tuntii

Cargo.lock

@@ -39,7 +39,7 @@ We optimize for **Developer Joy** without sacrificing **Req/Sec**.
 
 | Feature | **RustAPI** | Actix-web | Axum | FastAPI (Python) |
 |:-------|:-----------:|:---------:|:----:|:----------------:|
-| **Performance** | **~220k req/s** 🚀 | ~178k | ~165k | ~12k |
+| **Performance** | **~92k req/s** | ~105k | ~100k | ~12k |
 | **DX (Simplicity)** | 🟢 **High** | 🔴 Low | 🟡 Medium | 🟢 High |
 | **Boilerplate** | **Zero** | High | Medium | Zero |
 | **AI/LLM Native** | ✅ **Yes** | ❌ No | ❌ No | ❌ No |

README.md

@@ -106,7 +106,7 @@ async fn list_users() -> impl Responder {
             is_active: id % 2 == 0,
         })
         .collect();
-    
+
     HttpResponse::Ok().json(UsersListResponse {
         total: 100,
         page: 1,

benches/actix_bench_server/src/main.rs

@@ -100,7 +100,6 @@ async fn get_post(Path(id): Path<i64>) -> Json<PostResponse> {
     })
 }
 
-
 /// JSON request body parsing with validation
 #[rustapi_rs::post("/create-user")]
 #[rustapi_rs::tag("Benchmark")]
@@ -129,7 +128,7 @@ async fn list_users() -> Json<UsersListResponse> {
             is_active: id % 2 == 0,
         })
         .collect();
-    
+
     Json(UsersListResponse {
         total: 100,
         page: 1,

benches/bench_server/src/main.rs

@@ -0,0 +1 @@
+{"message":"Hello, World!"}

benches/test_body.json

@@ -22,6 +22,9 @@ http = { workspace = true }
 http-body-util = { workspace = true }
 bytes = { workspace = true }
 
+# Socket options
+socket2 = { version = "0.5", features = ["all"] }
+
 # Router
 matchit = { workspace = true }
 

crates/rustapi-core/Cargo.toml

@@ -64,6 +64,15 @@ pub fn from_slice_mut<T: DeserializeOwned>(slice: &mut [u8]) -> Result<T, JsonEr
 /// Serialize a value to a JSON byte vector.
 ///
 /// Uses pre-allocated buffer with estimated capacity for better performance.
+#[cfg(feature = "simd-json")]
+pub fn to_vec<T: Serialize>(value: &T) -> Result<Vec<u8>, JsonError> {
+    simd_json::to_vec(value).map_err(JsonError::SimdJson)
+}
+
+/// Serialize a value to a JSON byte vector.
+///
+/// Uses pre-allocated buffer with estimated capacity for better performance.
+#[cfg(not(feature = "simd-json"))]
 pub fn to_vec<T: Serialize>(value: &T) -> Result<Vec<u8>, JsonError> {
     serde_json::to_vec(value).map_err(JsonError::SerdeJson)
 }
@@ -72,6 +81,21 @@ pub fn to_vec<T: Serialize>(value: &T) -> Result<Vec<u8>, JsonError> {
 ///
 /// Use this when you have a good estimate of the output size to avoid
 /// reallocations.
+#[cfg(feature = "simd-json")]
+pub fn to_vec_with_capacity<T: Serialize>(
+    value: &T,
+    capacity: usize,
+) -> Result<Vec<u8>, JsonError> {
+    let mut buf = Vec::with_capacity(capacity);
+    simd_json::to_writer(&mut buf, value).map_err(JsonError::SimdJson)?;
+    Ok(buf)
+}
+
+/// Serialize a value to a JSON byte vector with pre-allocated capacity.
+///
+/// Use this when you have a good estimate of the output size to avoid
+/// reallocations.
+#[cfg(not(feature = "simd-json"))]
 pub fn to_vec_with_capacity<T: Serialize>(
     value: &T,
     capacity: usize,