diff --git a/is-html-fast/Cargo.lock b/is-html-fast/Cargo.lock
index 11ee252..5b8c4bc 100644
--- a/is-html-fast/Cargo.lock
+++ b/is-html-fast/Cargo.lock
@@ -99,31 +99,6 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
-[[package]]
-name = "crossbeam-deque"
-version = "0.8.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
-dependencies = [
- "crossbeam-epoch",
- "crossbeam-utils",
-]
-
-[[package]]
-name = "crossbeam-epoch"
-version = "0.9.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
-dependencies = [
- "crossbeam-utils",
-]
-
-[[package]]
-name = "crossbeam-utils"
-version = "0.8.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
-
 [[package]]
 name = "displaydoc"
 version = "0.2.5"
@@ -135,12 +110,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "either"
-version = "1.15.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
-
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -202,6 +171,21 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65bc07b1a8bc7c85c5f2e110c476c7389b4554ba72af57d8445ea63a576b0876"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.31"
@@ -218,12 +202,34 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "05f29059c0c2090612e8d742178b0580d2dc940c837851ad723096f87af6663e"
 
+[[package]]
+name = "futures-executor"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e28d1d997f585e54aebc3f97d39e72338912123a67330d723fdbb564d646c9f"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-io"
 version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e5c1b78ca4aae1ac06c48a526a655760685149f0d465d21f37abfe57ce075c6"
 
+[[package]]
+name = "futures-macro"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "162ee34ebcb7c64a8abebc059ce0fee27c2262618d7b60ed8faf72fef13c3650"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "futures-sink"
 version = "0.3.31"
@@ -242,8 +248,10 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9fa08315bb612088cc391249efdc3bc77536f16c91f6cf495e6fbe85b20a4a81"
 dependencies = [
+ "futures-channel",
  "futures-core",
  "futures-io",
+ "futures-macro",
  "futures-sink",
  "futures-task",
  "memchr",
@@ -561,8 +569,9 @@ dependencies = [
 name = "is-html-fast"
 version = "0.1.0"
 dependencies = [
- "rayon",
+ "futures",
  "reqwest",
+ "tokio",
 ]
 
 [[package]]
@@ -599,6 +608,16 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "241eaef5fd12c88705a01fc1066c48c4b36e0dd4377dcdc7ec3942cea7a69956"
 
+[[package]]
+name = "lock_api"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07af8b9cdd281b7915f413fa73f29ebd5d55d0d3f0155584dade1ff18cea1b17"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
 [[package]]
 name = "log"
 version = "0.4.27"
@@ -713,6 +732,29 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "parking_lot"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1bf18183cf54e8d6059647fc3063646a1801cf30896933ec2311622cc4b9a27"
+dependencies = [
+ "lock_api",
+ "parking_lot_core",
+]
+
+[[package]]
+name = "parking_lot_core"
+version = "0.9.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e401f977ab385c9e4e3ab30627d6f26d00e2c73eef317493c4ec6d468726cf8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "windows-targets",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
@@ -771,23 +813,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74765f6d916ee2faa39bc8e68e4f3ed8949b48cccdac59983d287a7cb71ce9c5"
 
 [[package]]
-name = "rayon"
-version = "1.10.0"
+name = "redox_syscall"
+version = "0.5.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+checksum = "928fca9cf2aa042393a8325b9ead81d2f0df4cb12e1e24cef072922ccd99c5af"
 dependencies = [
- "either",
- "rayon-core",
-]
-
-[[package]]
-name = "rayon-core"
-version = "1.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
-dependencies = [
- "crossbeam-deque",
- "crossbeam-utils",
+ "bitflags",
 ]
 
 [[package]]
@@ -921,6 +952,12 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
 [[package]]
 name = "security-framework"
 version = "2.11.1"
@@ -994,6 +1031,15 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9203b8055f63a2a00e2f593bb0510367fe707d7ff1e5c872de2f537b339e5410"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.9"
@@ -1116,11 +1162,25 @@ dependencies = [
  "bytes",
  "libc",
  "mio",
+ "parking_lot",
  "pin-project-lite",
+ "signal-hook-registry",
  "socket2",
+ "tokio-macros",
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "tokio-macros"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e06d43f1345a3bcd39f6a56dbb7dcab2ba47e68e8ac134855e7e2bdbaf8cab8"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "tokio-native-tls"
 version = "0.3.1"
diff --git a/is-html-fast/Cargo.toml b/is-html-fast/Cargo.toml
index 7ce4703..44d60d1 100644
--- a/is-html-fast/Cargo.toml
+++ b/is-html-fast/Cargo.toml
@@ -4,5 +4,6 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-rayon = "1.10.0"
+futures = "0.3.31"
 reqwest = { version = "0.12.19", features = ["blocking", "json"]}
+tokio = { version = "1", features = ["full"] }
diff --git a/is-html-fast/src/main.rs b/is-html-fast/src/main.rs
index 3d46a5a..68cb390 100644
--- a/is-html-fast/src/main.rs
+++ b/is-html-fast/src/main.rs
@@ -1,59 +1,67 @@
-use std::fs::{File, OpenOptions};
-use std::io::{BufRead, BufReader, Write};
-use std::sync::{Arc, Mutex};
+use std::fs::File;
+use std::io::Write;
 use std::time::Duration;
 
-use rayon::prelude::*;
-use reqwest::blocking::Client;
-use reqwest::header::CONTENT_TYPE;
+use futures::stream::{FuturesUnordered, StreamExt};
+use reqwest::Client;
+use tokio::fs;
+use tokio::io::AsyncBufReadExt;
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let input_file = File::open("domains.txt")?;
-    let reader = BufReader::new(input_file);
-    let domains: Vec<String> = reader.lines().filter_map(Result::ok).collect();
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let file = fs::File::open("domains.txt").await?;
+    let reader = tokio::io::BufReader::new(file);
+    let mut lines = reader.lines();
 
-    let output_file = OpenOptions::new()
-        .create(true)
-        .write(true)
-        .truncate(true)
-        .open("domains-filtered.txt")?;
+    let client = Client::builder()
+        .timeout(Duration::from_secs(5))
+        .build()?;
 
-    let output = Arc::new(Mutex::new(output_file));
+    let mut tasks = FuturesUnordered::new();
 
-    let client = Arc::new(
-        Client::builder()
-            .timeout(Duration::from_secs(5))
-            .build()?,
-    );
+    while let Some(line) = lines.next_line().await? {
+        let client = client.clone();
+        let domain = line.clone();
+        tasks.push(tokio::spawn(async move {
+            let url = format!("https://{}", domain);
+            let resp = client.get(&url).send().await;
 
-    domains.par_iter().for_each(|domain| {
-        let url = format!("https://{}", domain);
-        println!("Checking {}", url);
-
-        let response = client.get(&url).send();
-
-        match response {
-            Ok(resp) => {
-                if let Some(content_type) = resp.headers().get(CONTENT_TYPE) {
-                    if let Ok(content_type_str) = content_type.to_str() {
-                        if content_type_str.starts_with("text/html") {
-                            if let Ok(mut file) = output.lock() {
-                                writeln!(file, "{}", domain).ok();
+            match resp {
+                Ok(resp) => {
+                    if let Some(content_type) = resp.headers().get(reqwest::header::CONTENT_TYPE) {
+                        if let Ok(content_type_str) = content_type.to_str() {
+                            if content_type_str.starts_with("text/html") {
+                                println!("✅ HTML: {}", domain);
+                                return Some(domain);
+                            } else {
+                                println!("❌ Not HTML: {} ({})", domain, content_type_str);
                             }
-                            println!("✅ HTML: {}", domain);
-                        } else {
-                            println!("❌ Not HTML: {} ({})", domain, content_type_str);
                         }
+                    } else {
+                        println!("❌ No Content-Type: {}", domain);
                     }
-                } else {
-                    println!("❌ No Content-Type: {}", domain);
+                }
+                Err(_) => {
+                    println!("⚠️ Failed to connect: {}", domain);
                 }
             }
-            Err(_) => {
-                println!("⚠️ Failed to connect: {}", domain);
-            }
+
+            None
+        }));
+    }
+
+    let mut results = Vec::new();
+    while let Some(res) = tasks.next().await {
+        if let Ok(Some(domain)) = res {
+            results.push(domain);
         }
-    });
+    }
+
+    // 📝 한 번에 출력
+    let mut output = File::create("domains-filtered.txt")?;
+    for domain in results {
+        writeln!(output, "{}", domain)?;
+    }
 
     Ok(())
 }