diff --git a/Cargo.lock b/Cargo.lock
index 59d1c91..987cdee 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,6 +17,19 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "ahash"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e89da841a80418a9b391ebaea17f5c112ffaaa96f621d2c285b5174da76b9011"
+dependencies = [
+ "cfg-if",
+ "getrandom",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.3"
@@ -426,6 +439,17 @@ dependencies = [
  "pin-utils",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4567c8db10ae91089c99af84c68c38da3ec2f087c3f82960bcdbf3656b6f4d7"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "gimli"
 version = "0.29.0"
@@ -640,9 +664,9 @@ checksum = "97b3888a4aecf77e811145cadf6eef5901f4782c53886191b2f693f24761847c"
 
 [[package]]
 name = "libloading"
-version = "0.8.4"
+version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e310b3a6b5907f99202fcdb4960ff45b93735d7c7d96b760fcff8db2dc0e103d"
+checksum = "4979f22fdb869068da03c9f7528f8297c6fd2606bc3a4affe42e6a823fdb8da4"
 dependencies = [
  "cfg-if",
  "windows-targets 0.52.6",
@@ -783,9 +807,9 @@ checksum = "d231b230927b5e4ad203db57bbcbee2802f6bce620b1e4a9024a07d94e2907ec"
 
 [[package]]
 name = "portable-atomic"
-version = "1.6.0"
+version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
+checksum = "da544ee218f0d287a911e9c99a39a8c9bc8fcad3cb8db5959940044ecfc67265"
 
 [[package]]
 name = "powerfmt"
@@ -886,6 +910,7 @@ dependencies = [
 name = "pyreqwest_impersonate"
 version = "0.5.0"
 dependencies = [
+ "ahash",
  "encoding_rs",
  "indexmap",
  "pyo3",
@@ -1548,6 +1573,26 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "zerocopy"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.7.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "zstd"
 version = "0.13.2"
diff --git a/Cargo.toml b/Cargo.toml
index ceba63a..ea5b09a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,7 @@ reqwest-impersonate = { version = "0.11", default-features = false, features = [
     "zstd",
 ] }
 encoding_rs = { version = "0.8" }
+ahash = "0.8"
 indexmap = { version = "2", features = ["serde"] }
 tokio = { version = "1", features = ["rt"] }
 
diff --git a/src/lib.rs b/src/lib.rs
index 150eefe..934b8dd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,6 +2,7 @@ use std::str::FromStr;
 use std::sync::{Arc, OnceLock};
 use std::time::Duration;
 
+use ahash::RandomState;
 use indexmap::IndexMap;
 use pyo3::exceptions;
 use pyo3::prelude::*;
@@ -36,8 +37,8 @@ pub struct Client {
     client: Arc<reqwest_impersonate::Client>,
     auth: Option<(String, Option<String>)>,
     auth_bearer: Option<String>,
-    params: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
 }
 
 #[pymethods]
@@ -95,9 +96,9 @@ impl Client {
     fn new(
         auth: Option<(String, Option<String>)>,
         auth_bearer: Option<String>,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         cookie_store: Option<bool>,
         referer: Option<bool>,
         proxy: Option<&str>,
@@ -238,9 +239,9 @@ impl Client {
         py: Python,
         method: &str,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         content: Option<Vec<u8>>,
         data: Option<&Bound<'_, PyDict>>,
         json: Option<&Bound<'_, PyDict>>,
@@ -373,11 +374,11 @@ impl Client {
             })?;
 
             // Response items
-            let cookies: IndexMap<String, String> = resp
+            let cookies: IndexMap<String, String, RandomState> = resp
                 .cookies()
                 .map(|cookie| (cookie.name().to_string(), cookie.value().to_string()))
                 .collect();
-            let headers: IndexMap<String, String> = resp
+            let headers: IndexMap<String, String, RandomState> = resp
                 .headers()
                 .iter()
                 .map(|(k, v)| (k.as_str().to_string(), v.to_str().unwrap_or("").to_string()))
@@ -435,9 +436,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         auth: Option<(String, Option<String>)>,
         auth_bearer: Option<String>,
         timeout: Option<f64>,
@@ -464,9 +465,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         auth: Option<(String, Option<String>)>,
         auth_bearer: Option<String>,
         timeout: Option<f64>,
@@ -493,9 +494,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         auth: Option<(String, Option<String>)>,
         auth_bearer: Option<String>,
         timeout: Option<f64>,
@@ -522,9 +523,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         auth: Option<(String, Option<String>)>,
         auth_bearer: Option<String>,
         timeout: Option<f64>,
@@ -552,9 +553,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         content: Option<Vec<u8>>,
         data: Option<&Bound<'_, PyDict>>,
         json: Option<&Bound<'_, PyDict>>,
@@ -586,9 +587,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         content: Option<Vec<u8>>,
         data: Option<&Bound<'_, PyDict>>,
         json: Option<&Bound<'_, PyDict>>,
@@ -620,9 +621,9 @@ impl Client {
         &self,
         py: Python,
         url: &str,
-        params: Option<IndexMap<String, String>>,
-        headers: Option<IndexMap<String, String>>,
-        cookies: Option<IndexMap<String, String>>,
+        params: Option<IndexMap<String, String, RandomState>>,
+        headers: Option<IndexMap<String, String, RandomState>>,
+        cookies: Option<IndexMap<String, String, RandomState>>,
         content: Option<Vec<u8>>,
         data: Option<&Bound<'_, PyDict>>,
         json: Option<&Bound<'_, PyDict>>,
@@ -657,9 +658,9 @@ fn request(
     py: Python,
     method: &str,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     content: Option<Vec<u8>>,
     data: Option<&Bound<'_, PyDict>>,
     json: Option<&Bound<'_, PyDict>>,
@@ -710,9 +711,9 @@ fn request(
 fn get(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     auth: Option<(String, Option<String>)>,
     auth_bearer: Option<String>,
     timeout: Option<f64>,
@@ -754,9 +755,9 @@ fn get(
 fn head(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     auth: Option<(String, Option<String>)>,
     auth_bearer: Option<String>,
     timeout: Option<f64>,
@@ -798,9 +799,9 @@ fn head(
 fn options(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     auth: Option<(String, Option<String>)>,
     auth_bearer: Option<String>,
     timeout: Option<f64>,
@@ -842,9 +843,9 @@ fn options(
 fn delete(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     auth: Option<(String, Option<String>)>,
     auth_bearer: Option<String>,
     timeout: Option<f64>,
@@ -886,9 +887,9 @@ fn delete(
 fn post(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     content: Option<Vec<u8>>,
     data: Option<&Bound<'_, PyDict>>,
     json: Option<&Bound<'_, PyDict>>,
@@ -938,9 +939,9 @@ fn post(
 fn put(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     content: Option<Vec<u8>>,
     data: Option<&Bound<'_, PyDict>>,
     json: Option<&Bound<'_, PyDict>>,
@@ -990,9 +991,9 @@ fn put(
 fn patch(
     py: Python,
     url: &str,
-    params: Option<IndexMap<String, String>>,
-    headers: Option<IndexMap<String, String>>,
-    cookies: Option<IndexMap<String, String>>,
+    params: Option<IndexMap<String, String, RandomState>>,
+    headers: Option<IndexMap<String, String, RandomState>>,
+    cookies: Option<IndexMap<String, String, RandomState>>,
     content: Option<Vec<u8>>,
     data: Option<&Bound<'_, PyDict>>,
     json: Option<&Bound<'_, PyDict>>,
diff --git a/src/utils.rs b/src/utils.rs
index db9c3c5..01178e8 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,11 +1,14 @@
 use std::cmp::min;
 
+use ahash::RandomState;
 use indexmap::IndexMap;
 use pyo3::prelude::*;
 use pyo3::types::{PyBool, PyDict};
 
 // Get encoding from the "Content-Type" header
-pub fn get_encoding_from_headers(headers: &IndexMap<String, String>) -> Option<String> {
+pub fn get_encoding_from_headers(
+    headers: &IndexMap<String, String, RandomState>,
+) -> Option<String> {
     // Extract and decode the Content-Type header
     let content_type = headers
         .iter()
@@ -85,7 +88,7 @@ mod utils_tests {
     #[test]
     fn test_get_encoding_from_headers() {
         // Test case: Content-Type header with charset specified
-        let mut headers = IndexMap::new();
+        let mut headers = IndexMap::default();
         headers.insert(
             String::from("Content-Type"),
             String::from("text/html;charset=UTF-8"),