diff --git a/src/StevesBot.Worker.Tests/Unit/DiscordGatewayClientTests.cs b/src/StevesBot.Worker.Tests/Unit/DiscordGatewayClientTests.cs
index 6ea423e..2eec841 100644
--- a/src/StevesBot.Worker.Tests/Unit/DiscordGatewayClientTests.cs
+++ b/src/StevesBot.Worker.Tests/Unit/DiscordGatewayClientTests.cs
@@ -18,6 +18,18 @@ public sealed class DiscordGatewayClientTests : IDisposable
       .Setup(static x => x.GetUtcNow())
       .Returns(DateTimeOffset.UtcNow);
 
+    var mockServiceProvider = new Mock<IServiceProvider>();
+
+    var mockServiceScope = new Mock<IServiceScope>();
+
+    mockServiceScope
+      .Setup(static x => x.ServiceProvider)
+      .Returns(mockServiceProvider.Object);
+
+    _mockServiceScopeFactory
+      .Setup(static x => x.CreateScope())
+      .Returns(mockServiceScope.Object);
+
     _discordGatewayClient = new DiscordGatewayClient(
       _options,
       _mockWebSocketFactory.Object,
@@ -1056,9 +1068,92 @@ public sealed class DiscordGatewayClientTests : IDisposable
   }
 
   [Fact]
-  public Task On_WhenCalledWithValidEventAndHandler_ItShouldSubscribeHandlerToEvent()
+  public async Task On_WhenCalledWithValidEventAndHandler_ItShouldSubscribeHandlerToEvent()
   {
-    throw new NotImplementedException();
+    var readyHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+    var firstCreateMessageHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+    var secondCreateMessageHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+
+    secondCreateMessageHandler
+      .Setup(static x => x(It.IsAny<DiscordEvent>(), It.IsAny<IServiceProvider>(), It.IsAny<CancellationToken>()))
+      .ThrowsAsync(new Exception("This is a test exception"));
+
+    _discordGatewayClient.On(DiscordEventTypes.Ready, readyHandler.Object);
+    _discordGatewayClient.On(DiscordEventTypes.MessageCreate, firstCreateMessageHandler.Object);
+    _discordGatewayClient.On(DiscordEventTypes.MessageCreate, secondCreateMessageHandler.Object);
+
+    _mockDiscordRestClient
+      .Setup(static x => x.GetGatewayUrlAsync(It.IsAny<CancellationToken>()))
+      .ReturnsAsync("wss://gateway.discord.gg");
+
+    var socketState = WebSocketState.Closed;
+
+    var mockWebSocket = new Mock<IWebSocket>();
+
+    mockWebSocket
+      .Setup(static x => x.State)
+      .Returns(() => socketState);
+
+    mockWebSocket
+      .Setup(static x => x.ConnectAsync(It.IsAny<Uri>(), It.IsAny<CancellationToken>()))
+      .Callback(() => socketState = WebSocketState.Open)
+      .Returns(Task.CompletedTask);
+
+    var messagesToReceive = new Queue<(WebSocketReceiveResult, byte[])>();
+    var heartbeatInterval = 100;
+    var helloEvent = new HelloDiscordEvent()
+    {
+      Data = new()
+      {
+        HeartbeatInterval = heartbeatInterval,
+      }
+    };
+    var helloPayload = CreateEventPayload(helloEvent);
+    var helloResult = new WebSocketReceiveResult(helloPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((helloResult, helloPayload.Bytes));
+
+    var sessionId = "session_id";
+    var resumeGatewayUrl = "wss://resume.discord.gg";
+    var readyEvent = new ReadyDiscordEvent()
+    {
+      Data = new ReadyData()
+      {
+        SessionId = sessionId,
+        ResumeGatewayUrl = resumeGatewayUrl,
+      }
+    };
+    var readyPayload = CreateEventPayload(readyEvent);
+    var readyResult = new WebSocketReceiveResult(readyPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((readyResult, readyPayload.Bytes));
+
+    var heartbeatAckEvent = new HeartbeatAckDiscordEvent();
+    var heartbeatAckPayload = CreateEventPayload(heartbeatAckEvent);
+    var heartbeatAckResult = new WebSocketReceiveResult(heartbeatAckPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((heartbeatAckResult, heartbeatAckPayload.Bytes));
+
+    var messageCreateEvent = new MessageCreateDiscordEvent();
+    var messageCreatePayload = CreateEventPayload(messageCreateEvent);
+    var messageCreateResult = new WebSocketReceiveResult(
+      messageCreatePayload.Bytes.Length,
+      WebSocketMessageType.Text,
+      true
+    );
+    messagesToReceive.Enqueue((messageCreateResult, messageCreatePayload.Bytes));
+
+    SetupReceiveMessageSequence(mockWebSocket, messagesToReceive);
+
+    _mockWebSocketFactory
+      .Setup(static x => x.Create())
+      .Returns(mockWebSocket.Object);
+
+    using var cts = new CancellationTokenSource();
+    await _discordGatewayClient.ConnectAsync(cts.Token);
+    await Task.Delay(heartbeatInterval * 2);
+    await cts.CancelAsync();
+
+    readyHandler.Invocations.Should().HaveCount(1);
+    firstCreateMessageHandler.Invocations.Should().HaveCount(1);
+    secondCreateMessageHandler.Invocations.Should().HaveCount(1);
   }
 
   [Fact]
@@ -1077,9 +1172,92 @@ public sealed class DiscordGatewayClientTests : IDisposable
   }
 
   [Fact]
-  public Task Off_WhenCalledWithValidEventAndHandler_ItShouldUnsubscribeHandlerFromEvent()
+  public async Task Off_WhenCalledWithValidEventAndHandler_ItShouldUnsubscribeHandlerFromEvent()
   {
-    throw new NotImplementedException();
+    var readyHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+    var firstCreateMessageHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+    var secondCreateMessageHandler = new Mock<Func<DiscordEvent, IServiceProvider, CancellationToken, Task>>();
+
+    _discordGatewayClient.On(DiscordEventTypes.Ready, readyHandler.Object);
+    _discordGatewayClient.On(DiscordEventTypes.MessageCreate, firstCreateMessageHandler.Object);
+    _discordGatewayClient.On(DiscordEventTypes.MessageCreate, secondCreateMessageHandler.Object);
+
+    _discordGatewayClient.Off(DiscordEventTypes.MessageCreate, firstCreateMessageHandler.Object);
+    _discordGatewayClient.Off(DiscordEventTypes.Ready, readyHandler.Object);
+    _discordGatewayClient.Off(DiscordEventTypes.Ready, readyHandler.Object);
+
+    _mockDiscordRestClient
+      .Setup(static x => x.GetGatewayUrlAsync(It.IsAny<CancellationToken>()))
+      .ReturnsAsync("wss://gateway.discord.gg");
+
+    var socketState = WebSocketState.Closed;
+
+    var mockWebSocket = new Mock<IWebSocket>();
+
+    mockWebSocket
+      .Setup(static x => x.State)
+      .Returns(() => socketState);
+
+    mockWebSocket
+      .Setup(static x => x.ConnectAsync(It.IsAny<Uri>(), It.IsAny<CancellationToken>()))
+      .Callback(() => socketState = WebSocketState.Open)
+      .Returns(Task.CompletedTask);
+
+    var messagesToReceive = new Queue<(WebSocketReceiveResult, byte[])>();
+    var heartbeatInterval = 100;
+    var helloEvent = new HelloDiscordEvent()
+    {
+      Data = new()
+      {
+        HeartbeatInterval = heartbeatInterval,
+      }
+    };
+    var helloPayload = CreateEventPayload(helloEvent);
+    var helloResult = new WebSocketReceiveResult(helloPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((helloResult, helloPayload.Bytes));
+
+    var sessionId = "session_id";
+    var resumeGatewayUrl = "wss://resume.discord.gg";
+    var readyEvent = new ReadyDiscordEvent()
+    {
+      Data = new ReadyData()
+      {
+        SessionId = sessionId,
+        ResumeGatewayUrl = resumeGatewayUrl,
+      }
+    };
+    var readyPayload = CreateEventPayload(readyEvent);
+    var readyResult = new WebSocketReceiveResult(readyPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((readyResult, readyPayload.Bytes));
+
+    var heartbeatAckEvent = new HeartbeatAckDiscordEvent();
+    var heartbeatAckPayload = CreateEventPayload(heartbeatAckEvent);
+    var heartbeatAckResult = new WebSocketReceiveResult(heartbeatAckPayload.Bytes.Length, WebSocketMessageType.Text, true);
+    messagesToReceive.Enqueue((heartbeatAckResult, heartbeatAckPayload.Bytes));
+
+    var messageCreateEvent = new MessageCreateDiscordEvent();
+    var messageCreatePayload = CreateEventPayload(messageCreateEvent);
+    var messageCreateResult = new WebSocketReceiveResult(
+      messageCreatePayload.Bytes.Length,
+      WebSocketMessageType.Text,
+      true
+    );
+    messagesToReceive.Enqueue((messageCreateResult, messageCreatePayload.Bytes));
+
+    SetupReceiveMessageSequence(mockWebSocket, messagesToReceive);
+
+    _mockWebSocketFactory
+      .Setup(static x => x.Create())
+      .Returns(mockWebSocket.Object);
+
+    using var cts = new CancellationTokenSource();
+
+    await _discordGatewayClient.ConnectAsync(cts.Token);
+    await Task.Delay(heartbeatInterval * 2);
+    await cts.CancelAsync();
+
+    readyHandler.Invocations.Should().HaveCount(0);
+    firstCreateMessageHandler.Invocations.Should().HaveCount(0);
   }
 
   private static void SetupReceiveMessageSequence(
diff --git a/src/StevesBot.Worker.Tests/Unit/MessageCreateDiscordEventTests.cs b/src/StevesBot.Worker.Tests/Unit/MessageCreateDiscordEventTests.cs
index cb1f005..536e951 100644
--- a/src/StevesBot.Worker.Tests/Unit/MessageCreateDiscordEventTests.cs
+++ b/src/StevesBot.Worker.Tests/Unit/MessageCreateDiscordEventTests.cs
@@ -8,7 +8,7 @@ public class MessageCreateDiscordEventTests
     var result = new MessageCreateDiscordEvent();
 
     result.OpCode.Should().Be(0);
-    result.Type.Should().BeNull();
+    result.Type.Should().Be(DiscordEventTypes.MessageCreate);
     result.Sequence.Should().BeNull();
     result.Data.Should().BeEquivalentTo(new DiscordMessage());
   }
diff --git a/src/StevesBot.Worker/Discord/Gateway/Events/MessageCreateDiscordEvent.cs b/src/StevesBot.Worker/Discord/Gateway/Events/MessageCreateDiscordEvent.cs
index 6bb2bf8..23e6645 100644
--- a/src/StevesBot.Worker/Discord/Gateway/Events/MessageCreateDiscordEvent.cs
+++ b/src/StevesBot.Worker/Discord/Gateway/Events/MessageCreateDiscordEvent.cs
@@ -5,6 +5,11 @@ internal sealed record MessageCreateDiscordEvent : DispatchDiscordEvent
   [JsonPropertyName("d")]
   public new DiscordMessage Data { get; init; } = new DiscordMessage();
 
+  public MessageCreateDiscordEvent()
+  {
+    Type = DiscordEventTypes.MessageCreate;
+  }
+
   public bool IsMessageType(int messageType)
   {
     return Data.Type == messageType;
diff --git a/src/StevesBot.Worker/Discord/Gateway/Events/ReadyDiscordEvent.cs b/src/StevesBot.Worker/Discord/Gateway/Events/ReadyDiscordEvent.cs
index 0bcaa2a..afbdcbb 100644
--- a/src/StevesBot.Worker/Discord/Gateway/Events/ReadyDiscordEvent.cs
+++ b/src/StevesBot.Worker/Discord/Gateway/Events/ReadyDiscordEvent.cs
@@ -2,9 +2,13 @@ namespace StevesBot.Worker.Discord.Gateway.Events;
 
 internal sealed record ReadyDiscordEvent : DispatchDiscordEvent
 {
-  [JsonPropertyName("t")]
-  public new string Type { get; init; } = DiscordEventTypes.Ready;
 
   [JsonPropertyName("d")]
   public new ReadyData Data { get; init; } = new ReadyData();
+
+  public ReadyDiscordEvent()
+  {
+    Type = DiscordEventTypes.Ready;
+  }
 }
+