diff --git a/AMessanger.Core/Abstraction/IAccountService.cs b/AMessanger.Core/Abstraction/IAccountService.cs
new file mode 100644
index 0000000..d7bc8ff
--- /dev/null
+++ b/AMessanger.Core/Abstraction/IAccountService.cs
@@ -0,0 +1,11 @@
+using AMessanger.Core.DTO;
+using AMessanger.Core.Models;
+
+namespace AMessanger.Core.Abstraction;
+
+public interface IAccountService
+{
+    public Task<Result<Guid>> RegisterAsync(CreateUserDto dto, CancellationToken cancellationToken = default);
+
+    public Task<Result<string>> LoginAsync(string userName, string password, CancellationToken cancellationToken = default);
+}
\ No newline at end of file
diff --git a/AMessanger.Core/Abstraction/IUserService.cs b/AMessanger.Core/Abstraction/IUserService.cs
new file mode 100644
index 0000000..8ba766a
--- /dev/null
+++ b/AMessanger.Core/Abstraction/IUserService.cs
@@ -0,0 +1,19 @@
+using AMessanger.Core.DTO;
+using AMessanger.Core.Models;
+
+namespace AMessanger.Core.Abstraction;
+
+public interface IUserService
+{
+    public Task<Result<User>> CreateAsync(CreateUserDto dto, CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> GetByIdAsync(Guid id, CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> GetByUserNameAsync(string userName, CancellationToken cancellationToken = default);
+
+    public Task<Result<IEnumerable<User>>> GetAllAsync(CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> UpdateAsync(Guid id, UpdateUserDto dto, CancellationToken cancellationToken = default);
+
+    public Task<Result<Guid>> DeleteAsync(Guid id, CancellationToken cancellationToken = default);
+}
\ No newline at end of file
diff --git a/AMessanger.Core/Abstraction/IUsersRepository.cs b/AMessanger.Core/Abstraction/IUsersRepository.cs
new file mode 100644
index 0000000..6d730ff
--- /dev/null
+++ b/AMessanger.Core/Abstraction/IUsersRepository.cs
@@ -0,0 +1,19 @@
+using AMessanger.Core.Models;
+using AMessanger.Core.DTO;
+
+namespace AMessanger.Core.Abstraction;
+
+public interface IUsersRepository
+{
+    public Task<Result<Guid>> AddAsync(User user, CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> GetByIdAsync(Guid id, CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> GetByUserNameAsync(string userName, CancellationToken cancellationToken = default);
+
+    public Task<Result<IEnumerable<User>>> GetAllAsync(CancellationToken cancellationToken = default);
+
+    public Task<Result<User>> UpdateAsync(Guid id, UpdateUserDto dto, CancellationToken cancellationToken = default);
+
+    public Task<Result<Guid>> DeleteAsync(Guid id, CancellationToken cancellationToken = default);
+}
\ No newline at end of file
diff --git a/AMessanger.Core/DTO/CreateUserDto.cs b/AMessanger.Core/DTO/CreateUserDto.cs
new file mode 100644
index 0000000..083e9c8
--- /dev/null
+++ b/AMessanger.Core/DTO/CreateUserDto.cs
@@ -0,0 +1,6 @@
+namespace AMessanger.Core.DTO;
+
+public record class CreateUserDto(
+    string Name,
+    string Password
+);
\ No newline at end of file
diff --git a/AMessanger.Core/DTO/UpdateUserDto.cs b/AMessanger.Core/DTO/UpdateUserDto.cs
new file mode 100644
index 0000000..94cbbb1
--- /dev/null
+++ b/AMessanger.Core/DTO/UpdateUserDto.cs
@@ -0,0 +1,6 @@
+namespace AMessanger.Core.DTO;
+
+public record class UpdateUserDto(
+    string? Name,
+    string? Password
+);
\ No newline at end of file
diff --git a/AMessanger.Core/Result.cs b/AMessanger.Core/Result.cs
new file mode 100644
index 0000000..03fe9ae
--- /dev/null
+++ b/AMessanger.Core/Result.cs
@@ -0,0 +1,21 @@
+namespace AMessanger.Core;
+
+public class Result<T>
+{
+    public T? Value { get; }
+
+    public string? ErrorMessage { get; }
+
+    public bool IsSuccess { get; }
+
+    private Result(T? value, bool isSuccess, string? message)
+    {
+        Value = value;
+        IsSuccess = isSuccess;
+        ErrorMessage = message;
+    }
+
+    public static Result<T> Error(string message) => new(default, false, message);
+
+    public static Result<T> Success(T value) => new(value, true, null);
+}
\ No newline at end of file