Build Status


Socket.IO-client for iOS/OS X.


let socket = SocketIOClient(socketURL: "localhost:8080", options: [.Log(true), .ForcePolling(true)])

socket.on("connect") {data, ack in
    print("socket connected")

socket.on("currentAmount") {data, ack in
    if let cur = data[0] as? Double {
        socket.emitWithAck("canUpdate", cur)(timeoutAfter: 0) {data in
            socket.emit("update", ["amount": cur + 2.50])

        ack.with("Got your currentAmount", "dude")


Objective-C Example

SocketIOClient* socket = [[SocketIOClient alloc] initWithSocketURL:@"localhost:8080" options:@{@"log": @YES, @"forcePolling": @YES}];

[socket on:@"connect" callback:^(NSArray* data, SocketAckEmitter* ack) {
    NSLog(@"socket connected");

[socket on:@"currentAmount" callback:^(NSArray* data, SocketAckEmitter* ack) {
    double cur = [[data objectAtIndex:0] floatValue];

    [socket emitWithAck:@"canUpdate" withItems:@[@(cur)]](0, ^(NSArray* data) {
        [socket emit:@"update" withItems:@[@{@"amount": @(cur + 2.50)}]];

    [ack with:@[@"Got your currentAmount, ", @"dude"]];

[socket connect];


  • Supports 1.0+
  • Supports binary
  • Supports Polling and WebSockets
  • Supports TLS/SSL
  • Can be used from Objective-C


Requires Swift 2/Xcode 7

If you need Swift 1.2/Xcode 6.3/4 use v2.4.5 (Pre-Swift 2 support is no longer maintained)

If you need Swift 1.1/Xcode 6.2 use v1.5.2. (Pre-Swift 1.2 support is no longer maintained)

Manually (iOS 7+)

  1. Copy the Source folder into your Xcode project. (Make sure you add the files to your target(s))
  2. If you plan on using this from Objective-C, read this on exposing Swift code to Objective-C.

Swift Package Manager

Add the project as a dependency to your Package.swift:

import PackageDescription

let package = Package(
    name: "YourSocketIOProject",
    dependencies: [
        .Package(url: "", majorVersion: 4)

Then import import SocketIOClientSwift.


Add this line to your Cartfile:

github "socketio/" ~> 4.1.6 # Or latest version

Run carthage update --platform ios,macosx.

CocoaPods 0.36.0 or later (iOS 8+)

Create Podfile and add pod 'Socket.IO-Client-Swift':

source ''
platform :ios, '8.0'

pod 'Socket.IO-Client-Swift', '~> 4.1.6' # Or latest version

Install pods:

$ pod install

Import the module:


import Socket_IO_Client_Swift


#import <Socket_IO_Client_Swift/Socket_IO_Client_Swift-Swift.h>


Add this line to your Seedfile:

github "socketio/", "v4.1.6", :files => "SocketIOClientSwift/*.swift" # Or latest version

Run seed install.



init(var socketURL: String, options: Set<SocketIOClientOption> = []) - Creates a new SocketIOClient. opts is a Set of SocketIOClientOption. If your server is secure, you need to specify https in your socketURL.

convenience init(socketURL: String, options: NSDictionary?) - Same as above, but meant for Objective-C. See Options on how convert between SocketIOClientOptions and dictionary keys.


All options are a case of SocketIOClientOption. To get the Objective-C Option, convert the name to lowerCamelCase.

case ConnectParams([String: AnyObject]) // Dictionary whose contents will be passed with the connection.
case Reconnects(Bool) // Whether to reconnect on server lose. Default is `true`
case ReconnectAttempts(Int) // How many times to reconnect. Default is `-1` (infinite tries)
case ReconnectWait(Int) // Amount of time to wait between reconnects. Default is `10`
case ForcePolling(Bool) // `true` forces the client to use xhr-polling. Default is `false`
case ForceNew(Bool) // Will a create a new engine for each connect. Useful if you find a bug in the engine related to reconnects
case ForceWebsockets(Bool) // `true` forces the client to use WebSockets. Default is `false`
case Nsp(String) // The namespace to connect to. Must begin with /. Default is `/`
case Cookies([NSHTTPCookie]) // An array of NSHTTPCookies. Passed during the handshake. Default is nil.
case Log(Bool) // If `true` socket will log debug messages. Default is false.
case Logger(SocketLogger) // Custom logger that conforms to SocketLogger. Will use the default logging otherwise.
case SessionDelegate(NSURLSessionDelegate) // Sets an NSURLSessionDelegate for the underlying engine. Useful if you need to handle self-signed certs. Default is nil.
case Path(String) // If the server uses a custom path. ex: `"/swift"`. Default is `""`
case ExtraHeaders([String: String]) // Adds custom headers to the initial request. Default is nil.
case HandleQueue(dispatch_queue_t) // The dispatch queue that handlers are run on. Default is the main queue.
case VoipEnabled(Bool) // Only use this option if you're using the client with VoIP services. Changes the way the WebSocket is created. Default is false
case Secure(Bool) // If the connection should use TLS. Default is false.
case SelfSigned(Bool) // Sets WebSocket.selfSignedSSL (Don't do this, iOS will yell at you)


  1. on(event: String, callback: NormalCallback) -> NSUUID - Adds a handler for an event. Items are passed by an array. ack can be used to send an ack when one is requested. See example. Returns a unique id for the handler.
  2. once(event: String, callback: NormalCallback) -> NSUUID - Adds a handler that will only be executed once. Returns a unique id for the handler.
  3. onAny(callback:((event: String, items: AnyObject?)) -> Void) - Adds a handler for all events. It will be called on any received event.
  4. emit(event: String, _ items: AnyObject...) - Sends a message. Can send multiple items.
  5. emit(event: String, withItems items: [AnyObject]) - emit for Objective-C
  6. emitWithAck(event: String, _ items: AnyObject...) -> (timeoutAfter: UInt64, callback: (NSArray?) -> Void) -> Void - Sends a message that requests an acknowledgement from the server. Returns a function which you can use to add a handler. See example. Note: The message is not sent until you call the returned function.
  7. emitWithAck(event: String, withItems items: [AnyObject]) -> (UInt64, (NSArray?) -> Void) -> Void - emitWithAck for Objective-C. Note: The message is not sent until you call the returned function.
  8. connect() - Establishes a connection to the server. A "connect" event is fired upon successful connection.
  9. connect(timeoutAfter timeoutAfter: Int, withTimeoutHandler handler: (() -> Void)?) - Connect to the server. If it isn't connected after timeoutAfter seconds, the handler is called.
  10. close() - Closes the socket. Once a socket is closed it should not be reopened.
  11. reconnect() - Causes the client to reconnect to the server.
  12. joinNamespace(namespace: String) - Causes the client to join namespace. Shouldn't need to be called unless you change namespaces manually.
  13. leaveNamespace() - Causes the client to leave the nsp and go back to /
  14. off(event: String) - Removes all event handlers for event.
  15. off(id id: NSUUID) - Removes the event that corresponds to id.
  16. removeAllHandlers() - Removes all handlers.

Client Events

  1. connect - Emitted when on a successful connection.
  2. disconnect - Emitted when the connection is closed.
  3. error - Emitted on an error.
  4. reconnect - Emitted when the connection is starting to reconnect.
  5. reconnectAttempt - Emitted when attempting to reconnect.

Detailed Example

A more detailed example can be found here