diff --git a/account-service/pom.xml b/account-service/pom.xml
index f938bd9..cebeea4 100644
--- a/account-service/pom.xml
+++ b/account-service/pom.xml
@@ -72,6 +72,11 @@
             <artifactId>password4j</artifactId>
             <version>1.8.2</version>
         </dependency>
+        <dependency>
+            <groupId>com.googlecode.libphonenumber</groupId>
+            <artifactId>libphonenumber</artifactId>
+            <version>8.13.31</version>
+        </dependency>
     </dependencies>
 
     <build>
diff --git a/account-service/src/main/java/com/drinkool/RestAPI.java b/account-service/src/main/java/com/drinkool/RestAPI.java
index 29186e3..743f53a 100644
--- a/account-service/src/main/java/com/drinkool/RestAPI.java
+++ b/account-service/src/main/java/com/drinkool/RestAPI.java
@@ -1,7 +1,5 @@
 package com.drinkool;
 
-import java.util.UUID;
-
 import com.drinkool.dtos.*;
 import com.drinkool.models.Customer;
 
@@ -28,7 +26,7 @@ public class RestAPI {
     public Response quickSignup(QuickSignup input) {
         Customer newCustomer = new Customer();
 
-        newCustomer.signup(input.phone, UUID.randomUUID().toString().substring(0, 8));
+        newCustomer.signup(input.phone);
 
         return Response.status(Response.Status.CREATED).build();
     }
diff --git a/account-service/src/main/java/com/drinkool/models/User.java b/account-service/src/main/java/com/drinkool/models/User.java
index dea7dd0..80b071e 100644
--- a/account-service/src/main/java/com/drinkool/models/User.java
+++ b/account-service/src/main/java/com/drinkool/models/User.java
@@ -3,6 +3,11 @@ package com.drinkool.models;
 import io.quarkus.hibernate.orm.panache.PanacheEntity;
 import jakarta.persistence.*;
 import jakarta.transaction.*;
+import jakarta.ws.rs.BadRequestException;
+
+import java.util.UUID;
+
+import com.drinkool.utils.PhoneValidator;
 import com.password4j.Password;
 
 @Entity
@@ -23,14 +28,20 @@ public abstract class User extends PanacheEntity {
     }
 
     @Transactional
-    public void signup(String phone, String rawPassword) {
-        this.signup(phone, phone, rawPassword);
+    public void signup(String phone) {
+        this.signup(phone, phone, UUID.randomUUID().toString().substring(0, 32));
     }
 
     @Transactional
     public void signup(String name, String phone, String rawPassword) {
         this.name = name;
-        this.phone = phone;
+
+        if (!PhoneValidator.isValidInternationalPhone(phone)) {
+            throw new BadRequestException("InvalidPhoneNumber");
+        } else {
+            this.phone = phone;
+        }
+
         this.hashedPassword = Password.hash(rawPassword).withArgon2().getResult();
 
         this.persist();
diff --git a/account-service/src/main/java/com/drinkool/utils/PhoneValidator.java b/account-service/src/main/java/com/drinkool/utils/PhoneValidator.java
new file mode 100644
index 0000000..0aa97d5
--- /dev/null
+++ b/account-service/src/main/java/com/drinkool/utils/PhoneValidator.java
@@ -0,0 +1,18 @@
+package com.drinkool.utils;
+
+import com.google.i18n.phonenumbers.*;
+import com.google.i18n.phonenumbers.Phonenumber.PhoneNumber;
+
+public class PhoneValidator {
+    private static final PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
+
+    public static boolean isValidInternationalPhone(String phone) {
+        try {
+            PhoneNumber numberProto = phoneUtil.parse(phone, "VN");
+
+            return phoneUtil.isValidNumber(numberProto);
+        } catch (NumberParseException e) {
+            return false;
+        }
+    }
+}