diff --git a/Cargo.lock b/Cargo.lock
index f43c2fa..cd22f3a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -143,6 +143,16 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "bloomfilter"
+version = "3.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f6d7f06817e48ea4e17532fa61bc4e8b9a101437f0623f69d2ea54284f3a817"
+dependencies = [
+ "getrandom 0.2.16",
+ "siphasher",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.19.0"
@@ -180,6 +190,7 @@ checksum = "9555578bc9e57714c812a1f84e4fc5b4d21fcb063490c624de019f7464c91268"
 name = "client"
 version = "0.1.0"
 dependencies = [
+ "bloomfilter",
  "rand 0.9.1",
  "reqwest",
  "serde",
@@ -505,8 +516,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "335ff9f135e4384c8150d6f27c6daed433577f86b4750418338c01a1a2528592"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi 0.11.1+wasi-snapshot-preview1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -1617,6 +1630,12 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "siphasher"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56199f7ddabf13fe5074ce809e7d3f42b42ae711800501b5b16ea82ad029c39d"
+
 [[package]]
 name = "slab"
 version = "0.4.10"
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 2776a63..c572fe6 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+bloomfilter = "3.0.1"
 rand = "0.9.1"
 reqwest = { version = "0.12.22", features = ["json"] }
 serde = { version = "1.0.219", features = ["derive"] }
diff --git a/client/src/main.rs b/client/src/main.rs
index 0fcf15d..315cd7f 100644
--- a/client/src/main.rs
+++ b/client/src/main.rs
@@ -1,8 +1,11 @@
-use rand::distr::Alphabetic;
+use bloomfilter::Bloom;
+use rand::distr::{Alphabetic, Alphanumeric, SampleString};
 use rand::prelude::*;
 use reqwest::{Method, Request, Url};
 use serde::Deserialize;
+use serde::de::value::BoolDeserializer;
 use std::collections::HashMap;
+use std::hash::{DefaultHasher, Hash, Hasher};
 use std::time::Duration;
 
 #[derive(Deserialize, Debug)]
@@ -19,23 +22,30 @@ async fn main() {
         .build()
         .unwrap();
 
-    const users_url: &str = "http://localhost:9000/api/v1/user";
+    const USERS_URL: &str = "http://localhost:9000/api/v1/user";
 
     let mut rng = rand::rng();
     let mut ids = Vec::new();
+    let mut bf = Bloom::new_for_fp_rate(1000000usize, 0.0001f64).unwrap();
 
-    while true {
-        let uesrname: String = (1..rng.random_range(1..20))
-            .into_iter()
-            .map(|_| rand::rng().sample(rand::distr::Alphabetic) as char)
-            .collect();
-        let email = format!("{}@uocat.com", uesrname);
-        let mut map = HashMap::new();
-        map.insert("name", uesrname);
-        map.insert("email", email);
+    loop {
+        // let username: String = (4..rng.random_range(4..20))
+        //     .into_iter()
+        //     .map(|_| rand::rng().sample(rand::distr::Alphabetic) as char)
+        //     .collect();
+        let username_len = rng.random_range(4..20);
+        let username: String = Alphanumeric.sample_string(&mut rng, username_len);
+
+        if bf.check(&username) {
+            println!("Skip {username}");
+            continue;
+        }
+
+        let email = format!("{}@uocat.com", username);
+        let map = HashMap::from([("name", username.clone()), ("email", email)]);
 
         // send user request
-        let res = client.put(users_url).json(&map).send().await;
+        let res = client.put(USERS_URL).json(&map).send().await;
 
         if let Ok(res) = res {
             if res.status() == reqwest::StatusCode::OK {
@@ -44,6 +54,7 @@ async fn main() {
                     println!("Inserted {:?}", user);
                 }
             }
+            bf.set(&username);
         }
     }
 }