diff --git a/Cargo.lock b/Cargo.lock
index a596b51..989f16c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -305,6 +305,7 @@ dependencies = [
  "log",
  "matchit",
  "once_cell",
+ "parking_lot",
  "pyo3",
  "pyo3-asyncio-0-21",
  "serde",
diff --git a/Cargo.toml b/Cargo.toml
index ba4e028..d8c93af 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,6 +22,7 @@ once_cell = "1.19"
 # RFC 1738 / WHATWG: percent-decode and + as space in application/x-www-form-urlencoded query
 form_urlencoded = "1.2"
 log = "0.4"
+parking_lot = "0.12"
 
 [features]
 default = []
diff --git a/src/dispatch.rs b/src/dispatch.rs
index 218943f..11d769d 100644
--- a/src/dispatch.rs
+++ b/src/dispatch.rs
@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 use std::sync::Arc;
-use std::sync::Mutex;
+
+use parking_lot::Mutex;
 
 use jsonwebtoken::errors::ErrorKind;
 use jsonwebtoken::{decode, DecodingKey, Validation};
@@ -73,11 +74,11 @@ pub async fn run_rsgi(
     let is_head = method == "HEAD";
     if (method == "GET" || method == "HEAD") && path == "/openapi.json" {
         let (inc, doc) = {
-            let st = state.lock().map_err(crate::lock_err)?;
+            let st = state.lock();
             if !st.include_openapi {
                 (false, String::new())
             } else {
-                let oa = st.openapi.lock().map_err(crate::lock_err)?;
+                let oa = st.openapi.lock();
                 (true, oa.to_string())
             }
         };
@@ -121,7 +122,7 @@ pub async fn run_rsgi(
             ))
         })?;
     let route_out: Option<(usize, HashMap<String, String>)> = (|| -> PyResult<_> {
-        let st = state.lock().map_err(crate::lock_err)?;
+        let st = state.lock();
         let g = map_method_router(&st, &method)
             .ok_or_else(|| pyo3::exceptions::PyValueError::new_err("method"))?;
         Ok(g.at(&path).ok().map(|m| {
@@ -136,7 +137,7 @@ pub async fn run_rsgi(
         Some(x) => x,
         None => {
             let m = {
-                let st = state.lock().map_err(crate::lock_err)?;
+                let st = state.lock();
                 methods_matching_path(&st, &path)
             };
             if m.is_empty() {
@@ -169,7 +170,7 @@ pub async fn run_rsgi(
         handler_param_names,
         handler_varkw,
     ) = {
-        let st = state.lock().map_err(crate::lock_err)?;
+        let st = state.lock();
         let e = st
             .routes
             .get(route_idx)
diff --git a/src/lib.rs b/src/lib.rs
index bfc5115..8f83c97 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,7 @@
 use std::collections::HashSet;
 use std::sync::Arc;
-use std::sync::Mutex;
+
+use parking_lot::Mutex;
 
 use pyo3::prelude::*;
 use pyo3::types::{PyDict, PyList, PyTuple};
@@ -18,10 +19,6 @@ use state::AppState;
 
 type ParsedDependencies = (Vec<String>, Vec<Py<PyAny>>, Vec<bool>, Vec<bool>);
 
-pub(crate) fn lock_err<T>(e: std::sync::PoisonError<T>) -> PyErr {
-    pyo3::exceptions::PyRuntimeError::new_err(e.to_string())
-}
-
 /// Parameter names the route handler accepts, plus whether it has `**kwargs`.
 fn handler_signature_kinds(
     py: Python<'_>,
@@ -184,7 +181,7 @@ impl App {
         jwt_cookie: Option<String>,
         body_schema_json: Option<String>,
     ) -> PyResult<()> {
-        let st = self.state.lock().map_err(lock_err)?;
+        let st = self.state.lock();
         if st.frozen {
             return Err(pyo3::exceptions::PyValueError::new_err(
                 "app is frozen; no more add_route",
@@ -231,7 +228,7 @@ impl App {
             .getattr(pyo3::intern!(py, "__name__"))?
             .extract()?;
         let (handler_param_names, handler_varkw) = handler_signature_kinds(py, handler.bind(py))?;
-        let mut st = self.state.lock().map_err(lock_err)?;
+        let mut st = self.state.lock();
         let idx = st.routes.len();
         st.routes.push(state::RouteEntry {
             handler,
@@ -261,7 +258,7 @@ impl App {
             })?),
         };
         {
-            let mut oa = st.openapi.lock().map_err(lock_err)?;
+            let mut oa = st.openapi.lock();
             App::openapi_add_path(&mut oa, &method, &path, &op_id, request_schema);
         }
         {
@@ -276,20 +273,20 @@ impl App {
 
     /// Lock route registration. Linear dependency list is a valid topological order (DAG of independent roots).
     fn freeze(&self) -> PyResult<()> {
-        let mut st = self.state.lock().map_err(lock_err)?;
+        let mut st = self.state.lock();
         st.frozen = true;
         Ok(())
     }
 
     fn set_openapi_served(&self, enabled: bool) -> PyResult<()> {
-        let mut st = self.state.lock().map_err(lock_err)?;
+        let mut st = self.state.lock();
         st.include_openapi = enabled;
         Ok(())
     }
 
     fn set_openapi_title(&self, title: &str) -> PyResult<()> {
-        let st = self.state.lock().map_err(lock_err)?;
-        let mut oa = st.openapi.lock().map_err(lock_err)?;
+        let st = self.state.lock();
+        let mut oa = st.openapi.lock();
         if let Some(info) = oa
             .as_object_mut()
             .and_then(|m| m.get_mut("info"))
@@ -315,8 +312,8 @@ impl App {
     }
 
     fn openapi_json(&self) -> PyResult<String> {
-        let st = self.state.lock().map_err(lock_err)?;
-        let oa = st.openapi.lock().map_err(lock_err)?;
+        let st = self.state.lock();
+        let oa = st.openapi.lock();
         Ok(oa.to_string())
     }
 }
diff --git a/src/state.rs b/src/state.rs
index a4ffb39..981c936 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -1,7 +1,7 @@
 use std::collections::HashSet;
-use std::sync::Mutex;
 
 use matchit::Router;
+use parking_lot::Mutex;
 use pyo3::prelude::*;
 
 pub struct RouteEntry {
@@ -72,15 +72,15 @@ impl AppState {
 pub fn map_method_router<'a>(
     state: &'a AppState,
     method: &str,
-) -> Option<std::sync::MutexGuard<'a, matchit::Router<usize>>> {
+) -> Option<parking_lot::MutexGuard<'a, matchit::Router<usize>>> {
     match method {
         // RFC 9110: HEAD shares URI with GET; same handler, no body in the response.
-        "GET" | "HEAD" => state.get.lock().ok(),
-        "POST" => state.post.lock().ok(),
-        "PUT" => state.put.lock().ok(),
-        "PATCH" => state.patch.lock().ok(),
-        "DELETE" => state.delete.lock().ok(),
-        "OPTIONS" => state.options.lock().ok(),
+        "GET" | "HEAD" => Some(state.get.lock()),
+        "POST" => Some(state.post.lock()),
+        "PUT" => Some(state.put.lock()),
+        "PATCH" => Some(state.patch.lock()),
+        "DELETE" => Some(state.delete.lock()),
+        "OPTIONS" => Some(state.options.lock()),
         _ => None,
     }
 }
@@ -92,33 +92,39 @@ pub fn map_method_router<'a>(
 pub fn methods_matching_path(state: &AppState, path: &str) -> Vec<String> {
     const ORDER: [&str; 7] = ["GET", "HEAD", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"];
     let mut have = [false; 7];
-    if let Ok(g) = state.get.lock() {
+    {
+        let g = state.get.lock();
         if g.at(path).is_ok() {
             have[0] = true;
             have[1] = true;
         }
     }
-    if let Ok(r) = state.post.lock() {
+    {
+        let r = state.post.lock();
         if r.at(path).is_ok() {
             have[2] = true;
         }
     }
-    if let Ok(r) = state.put.lock() {
+    {
+        let r = state.put.lock();
         if r.at(path).is_ok() {
             have[3] = true;
         }
     }
-    if let Ok(r) = state.patch.lock() {
+    {
+        let r = state.patch.lock();
         if r.at(path).is_ok() {
             have[4] = true;
         }
     }
-    if let Ok(r) = state.delete.lock() {
+    {
+        let r = state.delete.lock();
         if r.at(path).is_ok() {
             have[5] = true;
         }
     }
-    if let Ok(r) = state.options.lock() {
+    {
+        let r = state.options.lock();
         if r.at(path).is_ok() {
             have[6] = true;
         }