diff --git a/Govor.API/Controllers/InviteController.cs b/Govor.API/Controllers/InviteController.cs
index 0da0c13..26ff900 100644
--- a/Govor.API/Controllers/InviteController.cs
+++ b/Govor.API/Controllers/InviteController.cs
@@ -1,4 +1,5 @@
-using Govor.API.Services;
+using Govor.Application.Interfaces;
+using Govor.Application.Interfaces.Infrastructure.Extensions;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 
@@ -9,24 +10,36 @@ namespace Govor.API.Controllers;
 public class InviteController : ControllerBase
 {
     private readonly IGroupService _groupService;
-
-    public InviteController(IGroupService groupService)
+    private readonly ILogger<InviteController> _logger;
+    private readonly ICurrentUserService _currentUser;
+    public InviteController(IGroupService groupService, 
+        ILogger<InviteController> logger)
     {
         _groupService = groupService;
+        _logger = logger;
     }
     
-    [HttpGet("{code}")]
     [Authorize]
+    [HttpGet("{code}")]
     public IActionResult JoinGroup(string code)
     {
-        var group = _groupService.GetGroupByInvite(code);
-        if (group == null) return NotFound();
-        
-        return Ok(new
+        try
         {
-            groupId = group.Id,
-            name = group.Name,
-            isChannel = group.IsChannel
-        });
+            _groupService.AddUserToGroupByInvitationAsync(_currentUser.GetCurrentUserId(), code);
+            
+            var group = _groupService.GetGroupByInviteCode(code);
+
+            return Ok(new
+            {
+                groupId = group.Id,
+                name = group.Name,
+                isChannel = group.IsChannel
+            });
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, ex.Message);
+            return StatusCode(500, ex.Message);
+        }
     }
 }
diff --git a/Govor.API/Hubs/ChatsHub.cs b/Govor.API/Hubs/ChatsHub.cs
index b61dba0..dd7f4eb 100644
--- a/Govor.API/Hubs/ChatsHub.cs
+++ b/Govor.API/Hubs/ChatsHub.cs
@@ -13,42 +13,138 @@ namespace Govor.API.Hubs;
 public class ChatsHub : Hub
 {
     private readonly ILogger<ChatsHub> _logger;
-    private readonly IChatService _chatService;
-    private readonly IGroupService _groupService;
+    private readonly IMessageService _messageService;
     
-    public ChatsHub(ILogger<ChatsHub> logger,
-        IChatService chatService
-        )
+    public ChatsHub(ILogger<ChatsHub> logger, IMessageService messageService)
     {
         _logger = logger;
-        _chatService = chatService;
+        _messageService = messageService;
     }
-
+    
     public override async Task OnConnectedAsync()
     {
         var userId = GetUserId();
-        
-        if (userId != Guid.Empty)
+        if (userId == Guid.Empty)
         {
-            // Binding ConnectionId to UserId
-            await Groups.AddToGroupAsync(Context.ConnectionId, userId.ToString());
-            _logger.LogInformation("User {UserId} connected with ConnectionId {ConnectionId}", userId, Context.ConnectionId);
+            _logger.LogWarning("User connected with invalid UserID claim.");
+            Context.Abort(); // Abort connection if userID is invalid
+            return;
         }
-        
+
+        // Add user to their own group (for private messages and notifications)
+        await Groups.AddToGroupAsync(Context.ConnectionId, userId.ToString());
+        _logger.LogInformation("User {UserId} connected with ConnectionId {ConnectionId} and added to their group", userId, Context.ConnectionId);
+
+        // TODO: Add user to their chat groups - this might require fetching user's groups from a service
+        // var userGroups = await _userService.GetUserGroupsAsync(userId);
+        // foreach (var group in userGroups)
+        // {
+        //     await Groups.AddToGroupAsync(Context.ConnectionId, $"group_{group.Id}");
+        // }
+
         await base.OnConnectedAsync();
     }
-
+    
     public override async Task OnDisconnectedAsync(Exception? exception)
     {
-        var userId = GetUserId();
+        var userId = GetUserId(suppressException: true); // Suppress exception if userID is not found (e.g. connection aborted early)
         if (userId != Guid.Empty)
         {
+            // Remove user from their own group
             await Groups.RemoveFromGroupAsync(Context.ConnectionId, userId.ToString());
-            _logger.LogInformation("User {UserId} disconnected", userId);
+            _logger.LogInformation("User {UserId} disconnected with ConnectionId {ConnectionId} and removed from their group", userId, Context.ConnectionId);
+
+            // TODO: Remove user from their chat groups
+            // var userGroups = await _userService.GetUserGroupsAsync(userId); // This might be problematic if the service relies on the user being connected
+            // foreach (var group in userGroups)
+            // {
+            //     await Groups.RemoveFromGroupAsync(Context.ConnectionId, $"group_{group.Id}");
+            // }
         }
+        else if (exception != null)
+        {
+            _logger.LogWarning(exception, "User disconnected with an exception and invalid UserID claim. ConnectionId: {ConnectionId}", Context.ConnectionId);
+        }
+        else
+        {
+            _logger.LogInformation("User disconnected with no exception and invalid UserID claim. ConnectionId: {ConnectionId}", Context.ConnectionId);
+        }
+
         await base.OnDisconnectedAsync(exception);
     }
 
+    public async Task Send(MessageRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.EncryptedContent) && (request.MediaAttachments == null || !request.MediaAttachments.Any()))
+        {
+            _logger.LogWarning("Empty message (no content and no attachments) received from user {UserId}", GetUserId());
+            throw new ArgumentException("Message cannot be empty (must have content or attachments).");
+        }
+
+        var senderId = GetUserId();
+        _logger.LogInformation("Message send initiated by {SenderId} to {RecipientId} of type {RecipientType}", senderId, request.RecipientId, request.RecipientType);
+
+        var sendMessageParams = new SendMessage(
+            EncryptContent: request.EncryptedContent,
+            ReplyToMessageId: request.ReplyToMessageId,
+            FromUserId: senderId,
+            RecipientId: request.RecipientId,
+            RecipientType: request.RecipientType,
+            SendAt: DateTime.UtcNow,
+            Media: request.MediaAttachments?.Select(f => new SendMedia(
+                f.MediaId, f.EncryptedKey, f.Type, f.MimeType)) ?? Array.Empty<SendMedia>()
+        );
+
+        try
+        {
+            var result = await _messageService.SendMessageAsync(sendMessageParams);
+            
+            if (!result.IsSuccess || result.MessageId == Guid.Empty)
+            {
+                _logger.LogError(result.Exception, "Failed to send message from {SenderId} to {RecipientId}. Error: {ErrorMessage}", senderId, request.RecipientId, result.Exception?.Message ?? "Unknown error");
+                if (result.Exception != null) throw result.Exception;
+                throw new HubException("Failed to send message due to an internal error.");
+            }
+
+            var messageResponse = new UserMessageResponse // Assuming a response DTO
+            {
+                MessageId = result.MessageId,
+                SenderId = senderId,
+                RecipientId = request.RecipientId,
+                RecipientType = request.RecipientType,
+                EncryptedContent = request.EncryptedContent,
+                SentAt = sendMessageParams.SendAt, 
+                IsEdited = false,
+                MediaAttachments = request.MediaAttachments,
+                ReplyToMessageId = request.ReplyToMessageId
+            };
+
+            // Notify recipient (user or group)
+            if (request.RecipientType == RecipientType.User)
+            {
+                // Send to the recipient's personal group
+                await Clients.Group(request.RecipientId.ToString()).SendAsync("ReceiveMessage", messageResponse);
+            }
+            else if (request.RecipientType == RecipientType.Group)
+            {
+                // Send to all members of the group, including the sender if they are part of the group via a different connection
+                await Clients.Group($"group_{request.RecipientId}").SendAsync("ReceiveMessage", messageResponse);
+            }
+
+            // Notify sender (confirmation) on their connection
+            await Clients.Caller.SendAsync("MessageSent", messageResponse); // Or use "ReceiveMessage" if the sender should also just get it like anyone else
+
+            _logger.LogInformation("Message {MessageId} sent successfully from {SenderId} to {RecipientId} ({RecipientType})", result.MessageId, senderId, request.RecipientId, request.RecipientType);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error sending message from {SenderId} to {RecipientId}", senderId, request.RecipientId);
+            // Consider sending a specific error message to the caller instead of a generic HubException or rethrowing.
+            // For example: await Clients.Caller.SendAsync("SendMessageFailed", new { Error = ex.Message });
+            throw new HubException("An error occurred while sending the message.", ex);
+        }
+    }
+
     public async Task Remove(Guid recipientId, Guid messageId)
     {
         
@@ -59,79 +155,19 @@ public class ChatsHub : Hub
         
     }
     
-    public async Task SendGroup(GroupMessageRequest request)
-    {
-        var senderId = GetUserId();
-
-        // Создание сообщения
-        var message = new SendMessage(
-            EncryptContent: request.EncryptedContent,
-            ReplyToMessageId: request.ReplyToMessageId,
-            FromUserId: senderId,
-            RecipientId: request.GroupId,
-            SendAt: DateTime.UtcNow,
-            Media: request.MediaAttachments?.Select(f => new SendMedia(
-                f.MediaId, f.EncryptedKey, f.Type, f.MimeType)) ?? Array.Empty<SendMedia>());
-
-        var result = await _groupService.SendMessageAsync(message);
-        
-        if (!result.IsSuccess)
-            throw result.Exception!;
-
-        // Шлём всем участникам группы, кроме отправителя
-        await Clients.GroupExcept($"group_{request.GroupId}", Context.ConnectionId)
-            .SendAsync("ReceiveGroupMessage", message);
-
-        // Отправителю тоже
-        await Clients.Caller.SendAsync("ReceiveGroupMessage", message);
-    }
     
-    public async Task Send(MessageRequest request)
-    {
-        if (string.IsNullOrWhiteSpace(request.EncryptedContent))
-        {
-            _logger.LogWarning("Empty message received from user {UserId}", GetUserId());
-            throw new ArgumentException("Message cannot be empty", nameof(request.EncryptedContent));
-        }
-        
-        var senderId = GetUserId();
-        
-        try
-        {
-            _logger.LogInformation("Message sent from {SenderId} to {RecipientId} at {UtcNow}", senderId, request.RecipientId, DateTime.UtcNow);
-            
-            var message = new SendMessage(
-                EncryptContent: request.EncryptedContent,
-                ReplyToMessageId: request.ReplyToMessageId,
-                FromUserId: senderId,
-                RecipientId: request.RecipientId,
-                SendAt: DateTime.UtcNow,
-                Media: request.MediaAttachments?.Select(f => new SendMedia(
-                    f.MediaId, f.EncryptedKey, f.Type, f.MimeType)) ?? Array.Empty<SendMedia>());
-
-            Result result = await _chatService.SendMessageAsync(message);
-            if(result.IsSuccess == false)
-                throw result.Exception;
-            
-            // Sending a message to the sender and recipient
-            await Clients.Group(message.RecipientId.ToString()).SendAsync("Receive", message);
-            await Clients.Group(message.FromUserId.ToString()).SendAsync("Receive", message);
-            // TODO: Send to Group 
-        }
-        catch (Exception ex)
-        {
-            _logger.LogError(ex, "Error sending message from {SenderId} to {RecipientId}", senderId, request.RecipientId);
-            throw;
-        }
-    }
     
-    private Guid GetUserId()
+    private Guid GetUserId(bool suppressException = false)
     {
         var userIdClaim = Context.User?.FindFirst("userID")?.Value;
         if (string.IsNullOrEmpty(userIdClaim) || !Guid.TryParse(userIdClaim, out var userId))
         {
-            _logger.LogError("Could not retrieve sender userId");
-            throw new UnauthorizedAccessException("userID claim is missing or invalid");
+            if (!suppressException)
+            {
+                _logger.LogError("Could not retrieve sender userId. Claim was: {UserIDClaim}", userIdClaim);
+                throw new UnauthorizedAccessException("userID claim is missing or invalid.");
+            }
+            return Guid.Empty;
         }
         return userId;
     }
diff --git a/Govor.Application/Interfaces/IGroupService.cs b/Govor.Application/Interfaces/IGroupService.cs
index 91ed51e..e57119c 100644
--- a/Govor.Application/Interfaces/IGroupService.cs
+++ b/Govor.Application/Interfaces/IGroupService.cs
@@ -1,9 +1,16 @@
-using Govor.Application.Interfaces.Messages;
+using Govor.Application.Interfaces.Messages.Parameters;
 using Govor.Core.Models;
 
-namespace Govor.API.Services;
+namespace Govor.Application.Interfaces;
 
-public interface IGroupService : IMessageSendingService, IMessageManagementService
+public interface IGroupService
 {
-    ChatGroup GetGroupByInvite(string code);
+    Task<ChatGroup> GetGroupByIdAsync(Guid groupId);
+    Task<ChatGroup> CreateGroupAsync(string name, Guid creatorId, IEnumerable<Guid> initialMemberIds);
+    Task<Result> AddUserToGroupByInvitationAsync(Guid userId, string invitationCode);
+    Task<Result> RemoveUserFromGroupAsync(Guid groupId, Guid userId, Guid removedByUserId);
+    Task<Result> DeleteGroupAsync(Guid groupId, Guid userId); 
+    Task<List<User>> GetGroupMembersAsync(Guid groupId); 
+    Task<List<ChatGroup>>GetUserGroupsAsync(Guid userId); 
+    ChatGroup GetGroupByInviteCode(string code);
 }
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/IChatService.cs b/Govor.Application/Interfaces/Messages/IChatService.cs
deleted file mode 100644
index e44dc9b..0000000
--- a/Govor.Application/Interfaces/Messages/IChatService.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-namespace Govor.Application.Interfaces.Messages;
-
-public interface IChatService : IMessageSendingService, IMessageManagementService
-{
-
-}
-
-
diff --git a/Govor.Application/Interfaces/Messages/IMessageManagementService.cs b/Govor.Application/Interfaces/Messages/IMessageManagementService.cs
deleted file mode 100644
index 9b35c43..0000000
--- a/Govor.Application/Interfaces/Messages/IMessageManagementService.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-using Govor.Application.Interfaces.Messages.Parameters;
-
-namespace Govor.Application.Interfaces.Messages;
-
-public interface IMessageManagementService
-{
-    Task<Result> EditMessageAsync(Guid editorId, Guid messageId, string newContent);
-    Task<Result> DeleteMessageAsync(Guid editorId, Guid messageId);
-}
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/IMessageReactionService.cs b/Govor.Application/Interfaces/Messages/IMessageReactionService.cs
deleted file mode 100644
index c8b624a..0000000
--- a/Govor.Application/Interfaces/Messages/IMessageReactionService.cs
+++ /dev/null
@@ -1,6 +0,0 @@
-namespace Govor.Application.Interfaces.Messages;
-
-public interface IMessageReactionService
-{
-    
-}
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/IMessageSendingService.cs b/Govor.Application/Interfaces/Messages/IMessageSendingService.cs
deleted file mode 100644
index 1bee95f..0000000
--- a/Govor.Application/Interfaces/Messages/IMessageSendingService.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-using Govor.Application.Interfaces.Messages.Parameters;
-
-namespace Govor.Application.Interfaces.Messages;
-
-public interface IMessageSendingService
-{
-    Task<Result> SendMessageAsync(SendMessage newMessage);
-}
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/IMessageService.cs b/Govor.Application/Interfaces/Messages/IMessageService.cs
new file mode 100644
index 0000000..850afcb
--- /dev/null
+++ b/Govor.Application/Interfaces/Messages/IMessageService.cs
@@ -0,0 +1,30 @@
+using Govor.Application.Interfaces.Messages.Parameters;
+using Govor.Core.Models;
+
+namespace Govor.Application.Interfaces.Messages;
+
+// Combining IChatService and IGroupService functionalities relevant to messages
+public interface IMessageService
+{
+    Task<SendMessageResult> SendMessageAsync(SendMessage messageParameters);
+    Task<EditMessageResult> EditMessageAsync(EditMessage messageParameters);
+    Task<DeleteMessageResult> DeleteMessageAsync(DeleteMessage messageParameters);
+    
+    // Potentially other message-related methods like:
+    // Task<GetMessagesResult> GetMessagesAsync(Guid userId, Guid chatId, RecipientType chatType, int pageNumber, int pageSize);
+    // Task<Result> MarkMessageAsReadAsync(Guid userId, Guid messageId);
+}
+
+// Define specific result types for clarity, including original message for notifications if needed
+
+public record SendMessageResult(bool IsSuccess, Exception? Exception, Guid MessageId) 
+    : Result(IsSuccess, Exception, MessageId);
+
+public record EditMessageResult(bool IsSuccess, Exception? Exception, Message? OriginalMessage) 
+    : Result(IsSuccess, Exception, OriginalMessage?.Id ?? Guid.Empty)
+{
+    // OriginalMessage can be useful for the Hub to know details like RecipientType, RecipientId for notifications
+}
+
+public record DeleteMessageResult(bool IsSuccess, Exception? Exception, Message? OriginalMessage) 
+    : Result(IsSuccess, Exception, OriginalMessage?.Id ?? Guid.Empty);
diff --git a/Govor.Application/Interfaces/Messages/Parameters/DeleteMessage.cs b/Govor.Application/Interfaces/Messages/Parameters/DeleteMessage.cs
new file mode 100644
index 0000000..ceed39d
--- /dev/null
+++ b/Govor.Application/Interfaces/Messages/Parameters/DeleteMessage.cs
@@ -0,0 +1,5 @@
+namespace Govor.Application.Interfaces.Messages.Parameters;
+
+public record DeleteMessage(
+    Guid DeleterId,
+    Guid MessageId);
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/Parameters/EditMessage.cs b/Govor.Application/Interfaces/Messages/Parameters/EditMessage.cs
new file mode 100644
index 0000000..4c0e6af
--- /dev/null
+++ b/Govor.Application/Interfaces/Messages/Parameters/EditMessage.cs
@@ -0,0 +1,7 @@
+namespace Govor.Application.Interfaces.Messages.Parameters;
+
+public record EditMessage(
+    Guid EditorId,
+    Guid MessageId,
+    string NewContent,
+    DateTime EditedAt);
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/Parameters/SendMedia.cs b/Govor.Application/Interfaces/Messages/Parameters/SendMedia.cs
index 06a002d..1d87a71 100644
--- a/Govor.Application/Interfaces/Messages/Parameters/SendMedia.cs
+++ b/Govor.Application/Interfaces/Messages/Parameters/SendMedia.cs
@@ -2,7 +2,4 @@ using Govor.Core.Models;
 
 namespace Govor.Application.Interfaces.Messages.Parameters;
 
-public record SendMedia(Guid Id,  
-    string EncryptedKey, 
-    MediaType Type,
-    string MimeType);
\ No newline at end of file
+public record SendMedia(Guid MediaId, string EncryptedKey, MediaType Type, string MimeType);
\ No newline at end of file
diff --git a/Govor.Application/Interfaces/Messages/Parameters/SendMessage.cs b/Govor.Application/Interfaces/Messages/Parameters/SendMessage.cs
index 23c7cc8..b302276 100644
--- a/Govor.Application/Interfaces/Messages/Parameters/SendMessage.cs
+++ b/Govor.Application/Interfaces/Messages/Parameters/SendMessage.cs
@@ -1,8 +1,11 @@
+using Govor.Core.Models;
+
 namespace Govor.Application.Interfaces.Messages.Parameters;
 
 public record SendMessage(
     string EncryptContent, 
     Guid? ReplyToMessageId,
+    RecipientType RecipientType,
     Guid RecipientId,
     Guid FromUserId,
     DateTime SendAt, 
diff --git a/Govor.Application/Services/MessageService.cs b/Govor.Application/Services/MessageService.cs
new file mode 100644
index 0000000..7131404
--- /dev/null
+++ b/Govor.Application/Services/MessageService.cs
@@ -0,0 +1,186 @@
+using Govor.Application.Interfaces;
+using Govor.Application.Interfaces.Messages;
+using Govor.Application.Interfaces.Messages.Parameters;
+using Govor.Core.Models;
+using Govor.Core.Repositories.Groups;
+using Govor.Core.Repositories.Messages;
+using Govor.Core.Repositories.Users;
+using Microsoft.Extensions.Logging;
+
+namespace Govor.Application.Services;
+
+public class MessageService : IMessageService
+{
+    private readonly IMessagesRepository _messagesRepository;
+    private readonly IUsersRepository _usersRepository; // For validating user recipients
+    private readonly IGroupsRepository _groupsRepository; // For validating group recipients and fetching members
+    private readonly IVerifyFriendship _verifyFriendship; // For private messages
+    private readonly ILogger<MessageService> _logger;
+
+    public MessageService(
+        IMessagesRepository messagesRepository,
+        IUsersRepository usersRepository,
+        IGroupsRepository groupsRepository,
+        IVerifyFriendship verifyFriendship,
+        ILogger<MessageService> logger)
+    {
+        _messagesRepository = messagesRepository;
+        _usersRepository = usersRepository;
+        _groupsRepository = groupsRepository;
+        _verifyFriendship = verifyFriendship;
+        _logger = logger;
+    }
+
+    public async Task<SendMessageResult> SendMessageAsync(SendMessage sendParams)
+    {
+        try
+        {
+            // Validate recipient
+            if (sendParams.RecipientType == RecipientType.User)
+            {
+                if (!await _usersRepository.ExistsByIdAsync(sendParams.RecipientId)) // Changed to ExistsByIdAsync
+                {
+                    _logger.LogWarning("Attempt to send message to non-existent user {RecipientId}", sendParams.RecipientId);
+                    return new SendMessageResult(false, new KeyNotFoundException($"Recipient user {sendParams.RecipientId} not found."), Guid.Empty);
+                }
+                // Verify friendship for private messages
+                await _verifyFriendship.VerifyAsync(sendParams.FromUserId, sendParams.RecipientId);
+            }
+            else if (sendParams.RecipientType == RecipientType.Group)
+            {
+                if (!_groupsRepository.Exists(sendParams.RecipientId))
+                {
+                    _logger.LogWarning("Attempt to send message to non-existent group {GroupId}", sendParams.RecipientId);
+                    return new SendMessageResult(false, new KeyNotFoundException($"Recipient group {sendParams.RecipientId} not found."), Guid.Empty);
+                }
+                // TODO: Optionally, verify if sender is a member of the group
+                // bool isMember = await _groupsRepository.IsUserMemberOfGroupAsync(sendParams.FromUserId, sendParams.RecipientId);
+                // if (!isMember)
+                // {
+                //    _logger.LogWarning("User {UserId} attempted to send message to group {GroupId} but is not a member", sendParams.FromUserId, sendParams.RecipientId);
+                //    return new SendMessageResult(false, new UnauthorizedAccessException("Sender is not a member of the group."), Guid.Empty);
+                // }
+            }
+            else
+            {
+                _logger.LogError("Invalid recipient type specified: {RecipientType}", sendParams.RecipientType);
+                return new SendMessageResult(false, new ArgumentException("Invalid recipient type."), Guid.Empty);
+            }
+
+            var messageId = Guid.NewGuid();
+            var message = new Message
+            {
+                Id = messageId,
+                SenderId = sendParams.FromUserId,
+                RecipientId = sendParams.RecipientId,
+                RecipientType = sendParams.RecipientType,
+                EncryptedContent = sendParams.EncryptContent,
+                SentAt = sendParams.SendAt,
+                IsEdited = false,
+                ReplyToMessageId = sendParams.ReplyToMessageId,
+                MediaAttachments = sendParams.Media?.Select(m => new MediaAttachments
+                {
+                    Id = m.MediaId, // Assuming SendMedia provides Id or it's generated here/by repo
+                    MessageId = messageId,
+                    Type = m.Type,
+                    MimeType = m.MimeType,
+                    EncryptedKey = m.EncryptedKey,
+                    // FilePath will be set by storage service or handled by repository if media ID is pre-generated
+                }).ToList() ?? new List<MediaAttachments>()
+            };
+
+            await _messagesRepository.AddAsync(message);
+            _logger.LogInformation("Message {MessageId} from {SenderId} to {RecipientId} ({RecipientType}) saved successfully.", messageId, sendParams.FromUserId, sendParams.RecipientId, sendParams.RecipientType);
+            return new SendMessageResult(true, null, messageId);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error sending message from {SenderId} to {RecipientId} ({RecipientType})", sendParams.FromUserId, sendParams.RecipientId, sendParams.RecipientType);
+            return new SendMessageResult(false, ex, Guid.Empty);
+        }
+    }
+
+    public async Task<EditMessageResult> EditMessageAsync(EditMessage editParams)
+    {
+        try
+        {
+            var message = await _messagesRepository.FindByIdAsync(editParams.MessageId);
+
+            if (message.SenderId != editParams.EditorId)
+            {
+                _logger.LogWarning("User {EditorId} attempted to edit message {MessageId} not sent by them (sender was {SenderId})", editParams.EditorId, editParams.MessageId, message.SenderId);
+                return new EditMessageResult(false, new UnauthorizedAccessException("User is not authorized to edit this message."), null);
+            }
+
+            // TODO: Add a time limit for editing messages? e.g., if (message.SentAt < DateTime.UtcNow.AddMinutes(-15)) throw new Exception("Edit time limit exceeded");
+            
+            // Keep a copy of the original message state for the result, if needed by Hub for notifications
+            var originalMessageForNotification = new Message
+            {
+                Id = message.Id,
+                SenderId = message.SenderId,
+                RecipientId = message.RecipientId,
+                RecipientType = message.RecipientType,
+                // Populate other fields if necessary for the notification
+            };
+
+            message.EncryptedContent = editParams.NewContent;
+            message.IsEdited = true;
+            message.EditedAt = editParams.EditedAt;
+
+            await _messagesRepository.UpdateAsync(message);
+            _logger.LogInformation("Message {MessageId} edited successfully by user {EditorId}", editParams.MessageId, editParams.EditorId);
+            return new EditMessageResult(true, null, originalMessageForNotification);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error editing message {MessageId} by user {EditorId}", editParams.MessageId, editParams.EditorId);
+            return new EditMessageResult(false, ex, null);
+        }
+    }
+
+    public async Task<DeleteMessageResult> DeleteMessageAsync(DeleteMessage deleteParams)
+    {
+        try
+        {
+            var message = await _messagesRepository.FindByIdAsync(deleteParams.MessageId);
+
+            if (message.SenderId != deleteParams.DeleterId)
+            {
+                // TODO: Allow group admins to delete messages in their groups?
+                // if (message.RecipientType == RecipientType.Group) {
+                //    bool isAdmin = await _groupsRepository.IsUserAdminOfGroupAsync(deleteParams.DeleterId, message.RecipientId);
+                //    if (!isAdmin) {
+                //        _logger.LogWarning("User {DeleterId} (not sender or admin) attempted to delete group message {MessageId}", deleteParams.DeleterId, deleteParams.MessageId);
+                //        return new DeleteMessageResult(false, new UnauthorizedAccessException("User is not authorized to delete this message."), null);
+                //    }
+                // } else {
+                   _logger.LogWarning("User {DeleterId} attempted to delete message {MessageId} not sent by them (sender was {SenderId})", deleteParams.DeleterId, deleteParams.MessageId, message.SenderId);
+                   return new DeleteMessageResult(false, new UnauthorizedAccessException("User is not authorized to delete this message."), null);
+                // }
+            }
+            
+            // Keep a copy of the original message state for the result, if needed by Hub for notifications
+            var originalMessageForNotification = new Message
+            {
+                Id = message.Id,
+                SenderId = message.SenderId,
+                RecipientId = message.RecipientId,
+                RecipientType = message.RecipientType,
+                // Populate other fields if necessary for the notification
+            };
+            
+            await _messagesRepository.RemoveAsync(deleteParams.MessageId);
+            
+            // TODO: Delete associated media attachments from storage if they are no longer referenced.
+
+            _logger.LogInformation("Message {MessageId} deleted successfully by user {DeleterId}", deleteParams.MessageId, deleteParams.DeleterId);
+            return new DeleteMessageResult(true, null, originalMessageForNotification);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error deleting message {MessageId} by user {DeleterId}", deleteParams.MessageId, deleteParams.DeleterId);
+            return new DeleteMessageResult(false, ex, null);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Govor.Application/Services/PrivateChatService.cs b/Govor.Application/Services/PrivateChatService.cs
deleted file mode 100644
index 786ad27..0000000
--- a/Govor.Application/Services/PrivateChatService.cs
+++ /dev/null
@@ -1,69 +0,0 @@
-using Govor.Application.Interfaces;
-using Govor.Application.Interfaces.Messages;
-using Govor.Application.Interfaces.Messages.Parameters;
-using Govor.Core.Models;
-using Govor.Core.Repositories.Messages;
-using Govor.Data;
-using Microsoft.EntityFrameworkCore;
-
-namespace Govor.Application.Services;
-
-public class PrivateChatService : IChatService
-{
-    private readonly IVerifyFriendship _verifyFriendship;
-    private readonly IMessagesRepository _messages;
-    
-    public PrivateChatService(IMessagesRepository messages, IVerifyFriendship verifyFriendship)
-    {
-        _messages = messages;
-        _verifyFriendship = verifyFriendship;
-    }
-    
-    public async Task<Result> SendMessageAsync(SendMessage newMessage)
-    {
-        try
-        {
-            await _verifyFriendship.VerifyAsync(newMessage.FromUserId, newMessage.RecipientId);
-
-            var messageId = Guid.NewGuid();
-            
-            var message = new Message()
-            {
-                Id = messageId,
-                EncryptedContent = newMessage.EncryptContent,
-                IsEdited = false,
-                SenderId = newMessage.FromUserId,
-                RecipientId = newMessage.RecipientId,
-                RecipientType = RecipientType.User,
-                ReplyToMessageId = newMessage.ReplyToMessageId,
-                
-                MediaAttachments = newMessage.Media.Select(m => new MediaAttachments()
-                {
-                    Id = m.Id,
-                    MessageId = messageId,
-                    Type = m.Type,
-                    MimeType = m.MimeType,
-                    EncryptedKey = m.EncryptedKey,
-                }).ToList()
-            };
-            
-            await _messages.AddAsync(message);
-            
-            return new Result(true, null, messageId);
-        }
-        catch (Exception ex)
-        {
-            return new Result(false, ex, Guid.Empty);
-        }
-    }
-
-    public Task<Result> EditMessageAsync(Guid editorId, Guid messageId, string newContent)
-    {
-        throw new NotImplementedException();
-    }
-
-    public Task<Result> DeleteMessageAsync(Guid editorId, Guid messageId)
-    {
-        throw new NotImplementedException();
-    }
-}
\ No newline at end of file
diff --git a/Govor.Contracts/Requests/SignalR/MessageRequest.cs b/Govor.Contracts/Requests/SignalR/MessageRequest.cs
index 09295d3..fdce57f 100644
--- a/Govor.Contracts/Requests/SignalR/MessageRequest.cs
+++ b/Govor.Contracts/Requests/SignalR/MessageRequest.cs
@@ -5,6 +5,7 @@ namespace Govor.Contracts.Requests.SignalR;
 public record MessageRequest
 {
     public Guid RecipientId { get; init; }
+    public RecipientType RecipientType { get; init; }
     public string EncryptedContent { get; init; } = string.Empty;
     public Guid? ReplyToMessageId { get; set; }
     public List<MediaReference> MediaAttachments { get; set; } = new();
diff --git a/Govor.Contracts/Responses/SignalR/UserMessageResponse.cs b/Govor.Contracts/Responses/SignalR/UserMessageResponse.cs
index fa98fc0..6380a05 100644
--- a/Govor.Contracts/Responses/SignalR/UserMessageResponse.cs
+++ b/Govor.Contracts/Responses/SignalR/UserMessageResponse.cs
@@ -1,12 +1,17 @@
 using Govor.Contracts.Requests.SignalR;
+using Govor.Core.Models;
 
 namespace Govor.Contracts.Responses.SignalR;
 
 public record UserMessageResponse
 {
-    public Guid Id { get; init; }
+    public Guid MessageId { get; init; }
     public Guid SenderId { get; init; }
+    public Guid RecipientId { get; init; }
+    public RecipientType RecipientType{get; init; }
     public string EncryptedContent { get; init; } = string.Empty;
-    public Guid? ReplyToMessageId { get; set; }
-    public List<MediaReference> MediaReferences { get; init; } = new List<MediaReference>();
+    public Guid? ReplyToMessageId { get; init; }
+    public DateTime SentAt { get; init; }
+    public bool IsEdited { get; init; } = false;
+    public List<MediaReference> MediaAttachments { get; init; } = new List<MediaReference>();
 }
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Groups/IGroupsExist.cs b/Govor.Core/Repositories/Groups/IGroupsExist.cs
new file mode 100644
index 0000000..4e95afa
--- /dev/null
+++ b/Govor.Core/Repositories/Groups/IGroupsExist.cs
@@ -0,0 +1,9 @@
+using Govor.Core.Models;
+
+namespace Govor.Core.Repositories.Groups;
+
+public interface IGroupsExist
+{
+    public bool Exists(Guid groupId);
+    public bool Exists(ChatGroup chatGroup);
+}
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Groups/IGroupsReader.cs b/Govor.Core/Repositories/Groups/IGroupsReader.cs
index 41f1924..df38bb8 100644
--- a/Govor.Core/Repositories/Groups/IGroupsReader.cs
+++ b/Govor.Core/Repositories/Groups/IGroupsReader.cs
@@ -1,6 +1,6 @@
 namespace Govor.Core.Repositories.Groups;
 
-public class IGroupsReader
+public interface IGroupsReader
 {
     
 }
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Groups/IGroupsRepository.cs b/Govor.Core/Repositories/Groups/IGroupsRepository.cs
new file mode 100644
index 0000000..cf9482f
--- /dev/null
+++ b/Govor.Core/Repositories/Groups/IGroupsRepository.cs
@@ -0,0 +1,6 @@
+namespace Govor.Core.Repositories.Groups;
+
+public interface IGroupsRepository : IGroupsReader, IGroupsExist, IGroupsWriter
+{
+    
+}
\ No newline at end of file
diff --git a/Govor.Core/Repositories/Groups/IGroupsWriter.cs b/Govor.Core/Repositories/Groups/IGroupsWriter.cs
new file mode 100644
index 0000000..2fc631c
--- /dev/null
+++ b/Govor.Core/Repositories/Groups/IGroupsWriter.cs
@@ -0,0 +1,6 @@
+namespace Govor.Core.Repositories.Groups;
+
+public interface IGroupsWriter
+{
+    
+}
\ No newline at end of file