diff --git a/JOBot.Backend/DAL/Context/AppDbContext.cs b/JOBot.Backend/DAL/Context/AppDbContext.cs
index a60473f..a8d79bb 100644
--- a/JOBot.Backend/DAL/Context/AppDbContext.cs
+++ b/JOBot.Backend/DAL/Context/AppDbContext.cs
@@ -8,4 +8,12 @@ class AppDbContext : DbContext
     public DbSet<User> Users { get; set; }
 
     public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {   
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.Entity<User>()
+            .HasAlternateKey(b => b.TelegramId);
+    }
 }
\ No newline at end of file
diff --git a/JOBot.Backend/DAL/Models/User.cs b/JOBot.Backend/DAL/Models/User.cs
index 5ce5d36..4767238 100644
--- a/JOBot.Backend/DAL/Models/User.cs
+++ b/JOBot.Backend/DAL/Models/User.cs
@@ -1,9 +1,15 @@
+using System.ComponentModel.DataAnnotations;
+using Microsoft.EntityFrameworkCore;
+
 namespace JOBot.Backend.DAL.Models;
 
+[PrimaryKey(nameof(Id))]
 public class User
 {
     public Guid Id { get; set; }
-    public long TelegramId { get; set; }
+
+    [Key]
+    public required long TelegramId { get; set; }
     public string? Username { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.Now;
 }
\ No newline at end of file
diff --git a/JOBot.Backend/Services/gRPC/UserService.cs b/JOBot.Backend/Services/gRPC/UserService.cs
index 3743a03..c265578 100644
--- a/JOBot.Backend/Services/gRPC/UserService.cs
+++ b/JOBot.Backend/Services/gRPC/UserService.cs
@@ -1,19 +1,36 @@
-namespace JOBot.Backend.Services.gRPC;
 
 using Grpc.Core;
 using JOBot.Proto;
+using JOBot.Backend.DAL.Context;
 
-class UserService : User.UserBase
+using Models = JOBot.Backend.DAL.Models;
+
+namespace JOBot.Backend.Services.gRPC;
+class UserService(AppDbContext dbContext) : User.UserBase
 {
+
     public override Task<RegisterResponse> Register(
         RegisterRequest request,
         ServerCallContext context)
-
     {
+        if(!dbContext.Users.Where(x => x.TelegramId == request.UserId)
+            .Any())
+        {
+            dbContext.Users.Add(new Models.User()
+            {
+                TelegramId = request.UserId,
+                Username = !string.IsNullOrEmpty(request.Username) ? request.Username : null
+            });
+
+            return Task.FromResult(new RegisterResponse
+            {
+                Success = true
+            });
+        }
 
         return Task.FromResult(new RegisterResponse
         {
-            UserId = request.UserId
+            Success = false
         });
     }
 }
\ No newline at end of file
diff --git a/Proto/user.proto b/Proto/user.proto
index ee50850..8fa07db 100644
--- a/Proto/user.proto
+++ b/Proto/user.proto
@@ -11,5 +11,5 @@ message RegisterRequest{
 }
 
 message RegisterResponse{
-	int64 user_id = 1;
+	bool success = 1;
 }
\ No newline at end of file