diff --git a/Socket.IO-Client-Swift.podspec b/Socket.IO-Client-Swift.podspec
index 2bd6493..636ca3d 100644
--- a/Socket.IO-Client-Swift.podspec
+++ b/Socket.IO-Client-Swift.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name         = "Socket.IO-Client-Swift"
   s.module_name  = "SocketIO"
-  s.version      = "16.0.0-beta1"
+  s.version      = "16.0.0-beta2"
   s.summary      = "Socket.IO-client for iOS and OS X"
   s.description  = <<-DESC
                    Socket.IO-client for iOS and OS X.
@@ -18,7 +18,7 @@ Pod::Spec.new do |s|
   s.requires_arc = true
   s.source = {
     :git => "https://github.com/socketio/socket.io-client-swift.git",
-    :tag => 'v16.0.0-beta1',
+    :tag => 'v16.0.0-beta2',
     :submodules => true
   }
 
diff --git a/Source/SocketIO/Client/SocketIOClient.swift b/Source/SocketIO/Client/SocketIOClient.swift
index 955e813..ca397fe 100644
--- a/Source/SocketIO/Client/SocketIOClient.swift
+++ b/Source/SocketIO/Client/SocketIOClient.swift
@@ -79,6 +79,7 @@ open class SocketIOClient: NSObject, SocketIOClientSpec {
     public private(set) var sid: String?
 
     let ackHandlers = SocketAckManager()
+    var connectPayload: [String: Any]?
 
     private(set) var currentAck = -1
 
@@ -107,8 +108,8 @@ open class SocketIOClient: NSObject, SocketIOClientSpec {
     /// Connect to the server. The same as calling `connect(timeoutAfter:withHandler:)` with a timeout of 0.
     ///
     /// Only call after adding your event listeners, unless you know what you're doing.
-    open func connect() {
-        connect(timeoutAfter: 0, withHandler: nil)
+    open func connect(withPayload payload: [String: Any]? = nil) {
+        connect(withPayload: payload, timeoutAfter: 0, withHandler: nil)
     }
 
     /// Connect to the server. If we aren't connected after `timeoutAfter` seconds, then `withHandler` is called.
@@ -118,7 +119,7 @@ open class SocketIOClient: NSObject, SocketIOClientSpec {
     /// - parameter timeoutAfter: The number of seconds after which if we are not connected we assume the connection
     ///                           has failed. Pass 0 to never timeout.
     /// - parameter handler: The handler to call when the client fails to connect.
-    open func connect(timeoutAfter: Double, withHandler handler: (() -> ())?) {
+    open func connect(withPayload payload: [String: Any]? = nil, timeoutAfter: Double, withHandler handler: (() -> ())?) {
         assert(timeoutAfter >= 0, "Invalid timeout: \(timeoutAfter)")
 
         guard let manager = self.manager, status != .connected else {
@@ -128,7 +129,7 @@ open class SocketIOClient: NSObject, SocketIOClientSpec {
 
         status = .connecting
 
-        joinNamespace()
+        joinNamespace(withPayload: payload)
 
         guard timeoutAfter != 0 else { return }
 
@@ -340,11 +341,15 @@ open class SocketIOClient: NSObject, SocketIOClientSpec {
         manager?.disconnectSocket(self)
     }
 
-    /// Joins `nsp`.
-    open func joinNamespace() {
+    /// Joins `nsp`. You shouldn't need to call this directly, instead call `connect`.
+    ///
+    /// - Parameter payload: The optional
+    open func joinNamespace(withPayload payload: [String: Any]? = nil) {
         DefaultSocketLogger.Logger.log("Joining namespace \(nsp)", type: logType)
 
-        manager?.connectSocket(self)
+        connectPayload = payload
+
+        manager?.connectSocket(self, withPayload: connectPayload)
     }
 
     /// Removes handler(s) for a client event.
diff --git a/Source/SocketIO/Client/SocketIOClientSpec.swift b/Source/SocketIO/Client/SocketIOClientSpec.swift
index 18b3d64..7813c53 100644
--- a/Source/SocketIO/Client/SocketIOClientSpec.swift
+++ b/Source/SocketIO/Client/SocketIOClientSpec.swift
@@ -65,16 +65,19 @@ public protocol SocketIOClientSpec : AnyObject {
     /// Connect to the server. The same as calling `connect(timeoutAfter:withHandler:)` with a timeout of 0.
     ///
     /// Only call after adding your event listeners, unless you know what you're doing.
-    func connect()
+    ///
+    /// - parameter payload: An optional payload sent on connect
+    func connect(withPayload payload: [String: Any]?)
 
     /// Connect to the server. If we aren't connected after `timeoutAfter` seconds, then `withHandler` is called.
     ///
     /// Only call after adding your event listeners, unless you know what you're doing.
     ///
+    /// - parameter payload: An optional payload sent on connect
     /// - parameter timeoutAfter: The number of seconds after which if we are not connected we assume the connection
     ///                           has failed. Pass 0 to never timeout.
     /// - parameter handler: The handler to call when the client fails to connect.
-    func connect(timeoutAfter: Double, withHandler handler: (() -> ())?)
+    func connect(withPayload payload: [String: Any]?, timeoutAfter: Double, withHandler handler: (() -> ())?)
 
     /// Called when the client connects to a namespace. If the client was created with a namespace upfront,
     /// then this is only called when the client connects to that namespace.
@@ -162,7 +165,9 @@ public protocol SocketIOClientSpec : AnyObject {
     func leaveNamespace()
 
     /// Joins `nsp`.
-    func joinNamespace()
+    ///
+    /// - Parameter withPayload: The payload to connect when joining this namespace
+    func joinNamespace(withPayload payload: [String: Any]?)
 
     /// Removes handler(s) for a client event.
     ///
diff --git a/Source/SocketIO/Manager/SocketManager.swift b/Source/SocketIO/Manager/SocketManager.swift
index e7b9d7f..4b579b4 100644
--- a/Source/SocketIO/Manager/SocketManager.swift
+++ b/Source/SocketIO/Manager/SocketManager.swift
@@ -202,7 +202,8 @@ open class SocketManager: NSObject, SocketManagerSpec, SocketParsable, SocketDat
     /// Connects a socket through this manager's engine.
     ///
     /// - parameter socket: The socket who we should connect through this manager.
-    open func connectSocket(_ socket: SocketIOClient) {
+    /// - parameter withPayload: Optional payload to send on connect
+    open func connectSocket(_ socket: SocketIOClient, withPayload payload: [String: Any]? = nil) {
         guard status == .connected else {
             DefaultSocketLogger.Logger.log("Tried connecting socket when engine isn't open. Connecting",
                                            type: SocketManager.logType)
@@ -211,7 +212,15 @@ open class SocketManager: NSObject, SocketManagerSpec, SocketParsable, SocketDat
             return
         }
 
-        engine?.send("0\(socket.nsp),", withData: [])
+        var payloadStr = ""
+
+        if payload != nil,
+           let payloadData = try? JSONSerialization.data(withJSONObject: payload!, options: .fragmentsAllowed),
+           let jsonString = String(data: payloadData, encoding: .utf8) {
+            payloadStr = jsonString
+        }
+
+        engine?.send("0\(socket.nsp),\(payloadStr)", withData: [])
     }
 
     /// Called when the manager has disconnected from socket.io.
@@ -341,7 +350,7 @@ open class SocketManager: NSObject, SocketManagerSpec, SocketParsable, SocketDat
         status = .connected
 
         for (_, socket) in nsps where socket.status == .connecting {
-            connectSocket(socket)
+            connectSocket(socket, withPayload: socket.connectPayload)
         }
     }
 
diff --git a/Source/SocketIO/Manager/SocketManagerSpec.swift b/Source/SocketIO/Manager/SocketManagerSpec.swift
index a5c6251..01acc32 100644
--- a/Source/SocketIO/Manager/SocketManagerSpec.swift
+++ b/Source/SocketIO/Manager/SocketManagerSpec.swift
@@ -91,7 +91,8 @@ public protocol SocketManagerSpec : AnyObject, SocketEngineClient {
     /// Connects a socket through this manager's engine.
     ///
     /// - parameter socket: The socket who we should connect through this manager.
-    func connectSocket(_ socket: SocketIOClient)
+    /// - parameter withPayload: Optional payload to send on connect
+    func connectSocket(_ socket: SocketIOClient, withPayload: [String: Any]?)
 
     /// Called when the manager has disconnected from socket.io.
     ///
diff --git a/Tests/TestSocketIO/SocketSideEffectTest.swift b/Tests/TestSocketIO/SocketSideEffectTest.swift
index 036f3ff..7440924 100644
--- a/Tests/TestSocketIO/SocketSideEffectTest.swift
+++ b/Tests/TestSocketIO/SocketSideEffectTest.swift
@@ -454,7 +454,7 @@ class SocketSideEffectTest: XCTestCase {
     }
 }
 
-struct ThrowingData : SocketData {
+struct ThrowingData: SocketData {
     enum ThrowingError : Error {
         case error
     }
@@ -465,7 +465,7 @@ struct ThrowingData : SocketData {
 
 }
 
-class TestEngine : SocketEngineSpec {
+class TestEngine: SocketEngineSpec {
     weak var client: SocketEngineClient?
     private(set) var closed = false
     private(set) var compress = false