diff --git a/core/scripts/hysteria2/add_user.sh b/core/scripts/hysteria2/add_user.sh
index 267c265..925484d 100644
--- a/core/scripts/hysteria2/add_user.sh
+++ b/core/scripts/hysteria2/add_user.sh
@@ -1,11 +1,7 @@
 #!/bin/bash
 
-# Source the path.sh script to load the necessary variables
 source /etc/hysteria/core/scripts/path.sh
-# source /etc/hysteria/core/scripts/utils.sh
-# define_colors
 
-# Function to add a new user to the configuration
 add_user() {
     if [ $# -ne 3 ] && [ $# -ne 5 ]; then
         echo "Usage: $0 <username> <traffic_limit_GB> <expiration_days> [password] [creation_date]"
@@ -18,45 +14,49 @@ add_user() {
     password=$4
     creation_date=$5
 
+    username_lower=$(echo "$username" | tr '[:upper:]' '[:lower:]')
+
     if [ -z "$password" ]; then
         password=$(pwgen -s 32 1)
     fi
     if [ -z "$creation_date" ]; then
         creation_date=$(date +%Y-%m-%d)
     else
-        # Validate the date format (YYYY-MM-DD)
         if ! [[ "$creation_date" =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]]; then
             echo "Invalid date format. Expected YYYY-MM-DD."
             exit 1
         fi
-        # Check if the date is valid
+
         if ! date -d "$creation_date" >/dev/null 2>&1; then
             echo "Invalid date. Please provide a valid date in YYYY-MM-DD format."
             exit 1
         fi
     fi
 
-    # Validate the username
     if ! [[ "$username" =~ ^[a-zA-Z0-9]+$ ]]; then
         echo -e "${red}Error:${NC} Username can only contain letters and numbers."
         exit 1
     fi
 
-    # Convert GB to bytes (1 GB = 1073741824 bytes)
     traffic=$(echo "$traffic_gb * 1073741824" | bc)
 
     if [ ! -f "$USERS_FILE" ]; then
         echo "{}" > "$USERS_FILE"
     fi
 
-    jq --arg username "$username" --arg password "$password" --argjson traffic "$traffic" --argjson expiration_days "$expiration_days" --arg creation_date "$creation_date" \
+    user_exists=$(jq --arg username "$username_lower" '
+        to_entries[] | select(.key | ascii_downcase == $username) | .key' "$USERS_FILE")
+
+    if [ -n "$user_exists" ]; then
+        echo "User already exists."
+        exit 1
+    fi
+
+    jq --arg username "$username_lower" --arg password "$password" --argjson traffic "$traffic" --argjson expiration_days "$expiration_days" --arg creation_date "$creation_date" \
     '.[$username] = {password: $password, max_download_bytes: $traffic, expiration_days: $expiration_days, account_creation_date: $creation_date, blocked: false}' \
     "$USERS_FILE" > "${USERS_FILE}.temp" && mv "${USERS_FILE}.temp" "$USERS_FILE"
 
-    # python3 "$CLI_PATH" restart-hysteria2 > /dev/null 2>&1
-
     echo -e "User $username added successfully."
 }
 
-# Call the function with the provided arguments
 add_user "$1" "$2" "$3" "$4" "$5"