diff --git a/back/Contracts/DTOs/UserDTO.cs b/back/Contracts/DTOs/UserDTO.cs
new file mode 100644
index 0000000..abf5f99
--- /dev/null
+++ b/back/Contracts/DTOs/UserDTO.cs
@@ -0,0 +1,9 @@
+namespace Contracts.DTO;
+
+public class UserDto
+{
+    public Guid? Id { get; set; }
+    public string? Username { get; set; }
+    public string? Password { get; set; }
+    public decimal? Balance { get; set; }
+}
\ No newline at end of file
diff --git a/back/Contracts/Repositories/IUserRepo.cs b/back/Contracts/Repositories/IUserRepo.cs
new file mode 100644
index 0000000..3785e5e
--- /dev/null
+++ b/back/Contracts/Repositories/IUserRepo.cs
@@ -0,0 +1,12 @@
+using Contracts.DTO;
+using Contracts.SearchModels;
+
+namespace Contracts.Repositories;
+
+public interface IUserRepo
+{
+    public Task<UserDto> Get(UserSearch search);
+    public Task<UserDto> Create(UserDto user);
+    public Task<UserDto> Update(UserDto user);
+    public Task<UserDto> Delete(UserSearch search);
+}
\ No newline at end of file
diff --git a/back/Contracts/SearchModels/UserSearch.cs b/back/Contracts/SearchModels/UserSearch.cs
new file mode 100644
index 0000000..7165750
--- /dev/null
+++ b/back/Contracts/SearchModels/UserSearch.cs
@@ -0,0 +1,6 @@
+namespace Contracts.SearchModels;
+
+public class UserSearch
+{
+    public Guid? Id { get; set; }
+}
\ No newline at end of file
diff --git a/back/Contracts/Services/IAuthService.cs b/back/Contracts/Services/IAuthService.cs
new file mode 100644
index 0000000..d6e5983
--- /dev/null
+++ b/back/Contracts/Services/IAuthService.cs
@@ -0,0 +1,12 @@
+using Contracts.DTO;
+using Contracts.ViewModels;
+
+namespace Contracts.Services;
+
+public interface IAuthService
+{
+    public Task<UserViewModel> Login();
+    public Task<UserViewModel> Register(UserDto user);
+    public Task<UserViewModel> UpdateUserData(UserDto user);
+    public Task<UserViewModel> Delete(Guid id);
+}
\ No newline at end of file
diff --git a/back/Contracts/ViewModels/UserViewModel.cs b/back/Contracts/ViewModels/UserViewModel.cs
new file mode 100644
index 0000000..9bf54dc
--- /dev/null
+++ b/back/Contracts/ViewModels/UserViewModel.cs
@@ -0,0 +1,8 @@
+namespace Contracts.ViewModels;
+
+public class UserViewModel
+{
+    public Guid Id { get; set; }
+    public string Name { get; set; } = string.Empty;
+    public decimal Balance { get; set; }
+}
\ No newline at end of file