diff --git a/index.ts b/index.ts
index b33e525..ab5dcab 100644
--- a/index.ts
+++ b/index.ts
@@ -49,10 +49,6 @@ app.use("/api/v1/user", userRoutes);
 app.use("/api/v1/users", usersRoutes);
 app.use("/api/v1/admin", adminRoutes);
 app.use("/api/v1/events", eventsRoutes);
-app.use("/api/v1/appstart", (req, res, next) => {
-  console.log("appstart");
-  res.status(200).json({ status: "ok" });
-});
 
 const specs = swaggerJsDoc(options);
 app.use("/api-docs", swaggerUI.serve, swaggerUI.setup(specs));
diff --git a/package-lock.json b/package-lock.json
index 50265b0..dbf9ef0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,7 +16,8 @@
         "mongoose": "^8.0.2",
         "morgan": "^1.10.0",
         "swagger-jsdoc": "^6.2.8",
-        "swagger-ui-express": "^5.0.0"
+        "swagger-ui-express": "^5.0.0",
+        "uuid": "^9.0.1"
       },
       "devDependencies": {
         "@types/bcrypt": "^5.0.2",
@@ -25,6 +26,7 @@
         "@types/node": "^20.10.2",
         "@types/swagger-jsdoc": "^6.0.4",
         "@types/swagger-ui-express": "^4.1.6",
+        "@types/uuid": "^9.0.7",
         "concurrently": "^8.2.2",
         "nodemon": "^3.0.2",
         "typescript": "^5.3.2"
@@ -263,6 +265,12 @@
         "@types/serve-static": "*"
       }
     },
+    "node_modules/@types/uuid": {
+      "version": "9.0.7",
+      "resolved": "https://registry.npmjs.org/@types/uuid/-/uuid-9.0.7.tgz",
+      "integrity": "sha512-WUtIVRUZ9i5dYXefDEAI7sh9/O7jGvHg7Df/5O/gtH3Yabe5odI3UWopVR1qbPXQtvOxWu3mM4XxlYeZtMWF4g==",
+      "dev": true
+    },
     "node_modules/@types/webidl-conversions": {
       "version": "7.0.3",
       "resolved": "https://registry.npmjs.org/@types/webidl-conversions/-/webidl-conversions-7.0.3.tgz",
@@ -2373,6 +2381,18 @@
         "node": ">= 0.4.0"
       }
     },
+    "node_modules/uuid": {
+      "version": "9.0.1",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-9.0.1.tgz",
+      "integrity": "sha512-b+1eJOlsR9K8HJpow9Ok3fiWOWSIcIzXodvv0rQjVoOVNpWMpxf1wZNpt4y9h10odCNrqnYp1OBzRktckBe3sA==",
+      "funding": [
+        "https://github.com/sponsors/broofa",
+        "https://github.com/sponsors/ctavan"
+      ],
+      "bin": {
+        "uuid": "dist/bin/uuid"
+      }
+    },
     "node_modules/validator": {
       "version": "13.11.0",
       "resolved": "https://registry.npmjs.org/validator/-/validator-13.11.0.tgz",
diff --git a/package.json b/package.json
index 4110a14..afaac3a 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,8 @@
     "mongoose": "^8.0.2",
     "morgan": "^1.10.0",
     "swagger-jsdoc": "^6.2.8",
-    "swagger-ui-express": "^5.0.0"
+    "swagger-ui-express": "^5.0.0",
+    "uuid": "^9.0.1"
   },
   "devDependencies": {
     "@types/bcrypt": "^5.0.2",
@@ -28,6 +29,7 @@
     "@types/node": "^20.10.2",
     "@types/swagger-jsdoc": "^6.0.4",
     "@types/swagger-ui-express": "^4.1.6",
+    "@types/uuid": "^9.0.7",
     "concurrently": "^8.2.2",
     "nodemon": "^3.0.2",
     "typescript": "^5.3.2"
diff --git a/src/controllers/userController.ts b/src/controllers/userController.ts
index 82611cd..e464dbf 100644
--- a/src/controllers/userController.ts
+++ b/src/controllers/userController.ts
@@ -6,21 +6,24 @@ import {
   decodeBase64,
   matchPassword,
   getUserSession,
+  getUser,
 } from "../utils/utils";
 import { isUsernameValid, isPasswordValid } from "../validation/validation";
 import { Session } from "../models/session";
-import { MONGODB_IGNORED_FIELDS } from "../utils/constants";
+import { MONGODB_IGNORED_FIELDS_USER } from "../utils/constants";
 
 export async function SignUp(req: Request, res: Response) {
   try {
-    const { AccountName, Username, Password } = req.body;
+    let { AccountName, Username, Password } = req.body;
 
     if (!AccountName || !Username || !Password) {
       return res.status(400).json({ status: "err" });
     }
 
-    const existingUser = await User.findOne({ AccountName })
-      .select(MONGODB_IGNORED_FIELDS)
+    AccountName = AccountName.toLowerCase();
+
+    const existingUser = await User.findOne({ accountName: AccountName })
+      .select(`accountName -_id`)
       .lean();
 
     if (existingUser) {
@@ -42,9 +45,9 @@ export async function SignUp(req: Request, res: Response) {
 
     user
       .save()
-      .then(() => saveSession(res, AccountName, Username))
+      .then(() => saveSession(res, user.userId, Username))
       .catch((err) => {
-        console.log(err);
+        console.error("error on signup saving session:", err);
         res.status(500).json({ status: "err" });
       });
   } catch (error) {
@@ -62,7 +65,7 @@ export async function Login(req: Request, res: Response) {
     }
 
     const user = await User.findOne({ accountName: AccountName })
-      .select(`accountName username password -_id`)
+      .select(`userId accountName username password -_id`)
       .lean();
 
     if (!user) {
@@ -85,7 +88,7 @@ export async function Login(req: Request, res: Response) {
       return res.status(401).json({ status: "err" });
     }
 
-    saveSession(res, user.accountName, user.username);
+    saveSession(res, user.userId, user.username);
   } catch (error) {
     console.error("error on login:", error);
     res.status(500).json({ status: "err" });
@@ -100,14 +103,14 @@ export async function ChangeUsername(req: Request, res: Response) {
       return res.status(400).json({ status: "err" });
     }
 
-    const session = await getUserSession(req, "accountName");
+    const session = await getUserSession(req, "userId");
 
     if (!session) {
       return res.status(401).json({ status: "err" });
     }
 
     await User.updateOne(
-      { accountName: session.accountName },
+      { userId: session.userId },
       { $set: { username: newUsername } }
     );
 
@@ -128,52 +131,46 @@ export async function ChangePassword(req: Request, res: Response) {
       return res.status(400).json({ status: "err" });
     }
 
-    console.log(cp, np);
+    const session = await getUserSession(req, "userId");
 
-    const session = await getUserSession(req, "accountName");
-
-    if (!session) {
+    if (!session || !session.userId) {
       return res.status(401).json({ status: "err" });
     }
 
-    const accountName = session.accountName;
-
     const decodedCurrentPassword = decodeBase64(cp);
 
-    const existingUser = await User.findOne({
-      accountName: accountName,
-    })
-      .select(`password -_id`)
-      .lean();
-
-    if (!existingUser) {
-      return res.status(400).json({ status: 1 });
-    }
-
-    const decodedNewPassword = decodeBase64(np);
-
     if (!isPasswordValid(decodedCurrentPassword)) {
       return res.status(400).json({ status: "err" });
     }
 
+    const userId = session.userId;
+
+    const existingUser = await getUser(userId);
+
+    if (!existingUser) {
+      return res.status(400).json({ status: 1 });
+    }
+
     const isPasswordMatching = await matchPassword(
       decodedCurrentPassword,
       existingUser.password
     );
 
+    const decodedNewPassword = decodeBase64(np);
+
     if (!isPasswordMatching || !isPasswordValid(decodedNewPassword)) {
       return res.status(401).json({ status: "err" });
     }
 
     await User.updateOne(
-      { accountName: accountName },
+      { userId: userId },
       { $set: { password: await hashPassword(decodedNewPassword) } }
     );
 
     res.status(200).json({ status: "ok" });
 
     // delete all sessions
-    await Session.deleteMany({ accountName: accountName });
+    await Session.deleteMany({ userId: userId });
   } catch (error) {
     console.error("error on changing password", error);
     res.status(500).json({ status: "err" });
@@ -196,3 +193,53 @@ export async function Logout(req: Request, res: Response) {
     res.status(500).json({ status: "err" });
   }
 }
+
+export async function IsAccountNameAvailable(req: Request, res: Response) {
+  try {
+    let { accountName } = req.params;
+
+    accountName = accountName.toLowerCase();
+
+    if (!accountName) {
+      return res.status(400).json({ status: "err" });
+    }
+
+    const existingUser = await User.findOne({ accountName: accountName })
+      .select(`accountName -_id`)
+      .lean();
+
+    if (existingUser) {
+      return res.status(422).json({ status: "not found" });
+    }
+
+    res.status(200).json({ status: "ok" });
+  } catch (error) {
+    console.error("error on checking account name availability", error);
+    res.status(500).json({ status: "err" });
+  }
+}
+
+// appstart
+export async function GetUserProfile(req: Request, res: Response) {
+  try {
+    const session = await getUserSession(req, "userId");
+
+    if (!session || !session.userId) {
+      return res.status(401).json({ status: "err" });
+    }
+
+    const user = await getUser(
+      session.userId,
+      `${MONGODB_IGNORED_FIELDS_USER} -createdAt`
+    );
+
+    if (!user) {
+      return res.status(404).json({ status: "err" });
+    }
+
+    res.json(user);
+  } catch (error) {
+    console.error("error on get user profile:", error);
+    res.status(500).json({ status: "err" });
+  }
+}
diff --git a/src/controllers/usersController.ts b/src/controllers/usersController.ts
index df94be6..1079043 100644
--- a/src/controllers/usersController.ts
+++ b/src/controllers/usersController.ts
@@ -4,10 +4,16 @@ import { MONGODB_IGNORED_FIELDS_USER } from "../utils/constants";
 
 export async function GetUserProfile(req: Request, res: Response) {
   try {
+    const { userId } = req.params;
+
+    if (!userId) {
+      return res.status(400).json({ status: "err" });
+    }
+
     const user = await User.findOne({
-      accountName: req.params.accountName,
+      id: userId,
     })
-      .select(`-accountName ${MONGODB_IGNORED_FIELDS_USER}`)
+      .select(`-id ${MONGODB_IGNORED_FIELDS_USER}`)
       .lean();
 
     if (!user) {
diff --git a/src/middleware/authMiddleware.ts b/src/middleware/authMiddleware.ts
index 0f2d80f..d1d4ddc 100644
--- a/src/middleware/authMiddleware.ts
+++ b/src/middleware/authMiddleware.ts
@@ -2,7 +2,7 @@ import { Request } from "express";
 import { Session } from "../models/session";
 import { User } from "../models/user";
 import { HEADER_X_AUTHORIZATION } from "../utils/constants";
-import { getUserSession } from "../utils/utils";
+import { getUser, getUserSession } from "../utils/utils";
 
 export async function sessionProtection(req: Request, res: any, next: any) {
   const session = await getUserSession(req);
@@ -22,16 +22,14 @@ export async function adminProtection(req: Request, res: any, next: any) {
   }
 
   const session = await Session.findOne({ sessionId: xAuthorization })
-    .select("sessionId accountName -_id")
+    .select("sessionId userId -_id")
     .lean();
 
-  if (!session) {
+  if (!session || !session.userId) {
     return res.status(401).json({ status: "err" });
   }
 
-  const user = await User.findOne({ accountName: session.accountName })
-    .select("isAdmin -_id")
-    .lean();
+  const user = await getUser(session.userId, "isAdmin");
 
   if (!user || !user.isAdmin) {
     return res.status(401).json({ status: "err" });
diff --git a/src/models/session.ts b/src/models/session.ts
index 459250a..0c2279a 100644
--- a/src/models/session.ts
+++ b/src/models/session.ts
@@ -3,7 +3,7 @@ import { DEFAULT_SESSION_EXPIRATION } from "../utils/constants";
 
 export const sessionSchema = new Schema({
   sessionId: String,
-  accountName: String,
+  userId: String,
   expiresAt: {
     type: Date,
     default: new Date(Date.now() + DEFAULT_SESSION_EXPIRATION),
diff --git a/src/models/user.ts b/src/models/user.ts
index a0c0e61..84af69f 100644
--- a/src/models/user.ts
+++ b/src/models/user.ts
@@ -1,6 +1,8 @@
 import mongoose, { InferSchemaType, Schema } from "mongoose";
+import { v4 as uuidv4 } from "uuid";
 
 export interface IUser extends Document {
+  userId: string;
   accountName: string;
   username: string;
   password: string;
@@ -8,9 +10,16 @@ export interface IUser extends Document {
   following: number;
   visited: number;
   isAdmin: boolean;
+  createdAt: Date;
 }
 
 export const userSchema = new Schema({
+  userId: {
+    type: String,
+    required: true,
+    unique: true,
+    default: () => uuidv4(),
+  },
   accountName: String,
   username: String,
   password: String,
@@ -30,6 +39,10 @@ export const userSchema = new Schema({
     type: Boolean,
     default: false,
   },
+  createdAt: {
+    type: Date,
+    default: Date.now(),
+  },
 });
 
 export type User = InferSchemaType<typeof userSchema>;
diff --git a/src/routes/userRoutes.ts b/src/routes/userRoutes.ts
index 5dc7c7d..5e02933 100644
--- a/src/routes/userRoutes.ts
+++ b/src/routes/userRoutes.ts
@@ -130,5 +130,7 @@ router.post("/login", userController.Login);
 router.post("/username", sessionProtection, userController.ChangeUsername);
 router.post("/password", sessionProtection, userController.ChangePassword);
 router.post("/logout", sessionProtection, userController.Logout);
+router.get("/check/:accountName", userController.IsAccountNameAvailable);
+router.get("/", sessionProtection, userController.GetUserProfile);
 
 export default router;
diff --git a/src/routes/usersRoutes.ts b/src/routes/usersRoutes.ts
index 449399a..f87c2bf 100644
--- a/src/routes/usersRoutes.ts
+++ b/src/routes/usersRoutes.ts
@@ -3,6 +3,6 @@ const router = express.Router();
 import * as usersController from "../controllers/usersController";
 import { sessionProtection } from "../middleware/authMiddleware";
 
-router.get("/:accountName", sessionProtection, usersController.GetUserProfile);
+router.get("/:userId", sessionProtection, usersController.GetUserProfile);
 
 export default router;
diff --git a/src/utils/constants.ts b/src/utils/constants.ts
index 733734e..466a781 100644
--- a/src/utils/constants.ts
+++ b/src/utils/constants.ts
@@ -12,6 +12,7 @@ export const MONGODB_IGNORED_FIELDS_USER: string =
 // Header name for the session ID
 export const HEADER_X_AUTHORIZATION: string = "x-authorization";
 
+// Regular expressions and length requirements
 export const USERNAME_MIN_LENGTH: number = 2;
 export const USERNAME_MAX_LENGTH: number = 24;
 export const USERNAME_REGEX: RegExp = /^[a-zA-Z0-9_]+$/; // Alphanumeric and underscore
diff --git a/src/utils/utils.ts b/src/utils/utils.ts
index b2c10bd..ea18b14 100644
--- a/src/utils/utils.ts
+++ b/src/utils/utils.ts
@@ -2,11 +2,12 @@ import crypto from "crypto";
 import { Session } from "../models/session";
 import { Request, Response } from "express";
 import bcrypt from "bcrypt";
-import { HEADER_X_AUTHORIZATION } from "./constants";
+import { HEADER_X_AUTHORIZATION, MONGODB_IGNORED_FIELDS } from "./constants";
+import { User } from "../models/user";
 
 export async function saveSession(
   res: Response,
-  accountName: string,
+  userId: string,
   username: string
 ) {
   try {
@@ -16,14 +17,16 @@ export async function saveSession(
     // Create a new session document
     const session = new Session({
       sessionId: sessionId,
-      accountName: accountName, // Assuming you have the user information in req.user
+      userId: userId,
     });
 
     // Save the session to MongoDB
     await session.save();
 
     // Respond with the session ID
-    res.status(200).json({ XAuthorization: sessionId, Username: username });
+    res
+      .status(200)
+      .json({ XAuthorization: sessionId, UserId: userId, Username: username });
   } catch (error) {
     console.error("Error saving session:", error);
     res.status(500).json({ status: "err" });
@@ -43,19 +46,34 @@ export function decodeBase64(value: string) {
 }
 
 export async function getUserSession(req: Request, select?: string) {
+  // Get the session ID from the request headers
   const sessionId = req.get(HEADER_X_AUTHORIZATION);
 
   if (!sessionId) {
     return null;
   }
 
+  // Find the session in MongoDB
   const session = await Session.findOne({ sessionId })
     .select(`sessionId -_id ${select}`)
     .lean();
 
+  // Return the session
   if (!session) {
     return null;
   }
 
   return session;
 }
+
+export async function getUser(userId: string, select?: string) {
+  const user = await User.findOne({ userId: userId })
+    .select(select ? select : "")
+    .lean();
+
+  if (!user) {
+    return null;
+  }
+
+  return user;
+}