SwiftWebSocket 2.7.0

SwiftWebSocket 2.7.0

LangLanguage SwiftSwift
License Custom
ReleasedLast Release Feb 2018
SPMSupports SPM

Maintained by Josh Baker.


Conforming WebSocket (RFC 6455) client library for iOS and Mac OSX.

SwiftWebSocket passes all 521 of the Autobahn’s fuzzing tests, including strict UTF-8, and message compression.


  • High performance.
  • 100% conforms to Autobahn Tests. Including base, limits, compression, etc. Test results.
  • TLS / WSS support. Self-signed certificate option.
  • The API is modeled after the Javascript API.
  • Reads compressed messages (permessage-deflate). RFC 7692
  • Send pings and receive pong events.
  • Strict UTF-8 processing.
  • binaryType property to choose between [UInt8] or NSData messages.
  • Zero asserts. All networking, stream, and protocol errors are routed through the error event.
  • iOS / Objective-C support.


func echoTest(){
    var messageNum = 0
    let ws = WebSocket("wss://echo.websocket.org")
    let send : ()->() = {
        messageNum += 1
        let msg = "\(messageNum): \(NSDate().description)"
        print("send: \(msg)")
    ws.event.open = {
    ws.event.close = { code, reason, clean in
    ws.event.error = { error in
        print("error \(error)")
    ws.event.message = { message in
        if let text = message as? String {
            print("recv: \(text)")
            if messageNum == 10 {
            } else {

Custom Headers

let request = NSMutableURLRequest(URL: NSURL(string:"ws://url")!)
request.addValue("AUTH_TOKEN", forHTTPHeaderField: "Authorization")
request.addValue("Value", forHTTPHeaderField: "X-Another-Header")
let ws = WebSocket(request: request)

Reuse and Delaying WebSocket Connections

v2.3.0+ makes available an optional open method. This will allow for a WebSocket object to be instantiated without an immediate connection to the server. It can also be used to reconnect to a server following the close event.

For example,

let ws = WebSocket()
ws.event.close = { _ in
    ws.open()                 // reopen the socket to the previous url
    ws.open("ws://otherurl")  // or, reopen the socket to a new url
ws.open("ws://url") // call with url


The compression flag may be used to request compressed messages from the server. If the server does not support or accept the request, then connection will continue as normal, but with uncompressed messages.

let ws = WebSocket("ws://url")
ws.compression.on = true

Self-signed SSL Certificate

let ws = WebSocket("ws://url")
ws.allowSelfSignedSSL = true

Network Services (VoIP, Video, Background, Voice)

// Allow socket to handle VoIP in the background.
ws.services = [.VoIP, .Background] 


Josh Baker @tidwall


SwiftWebSocket source code is available under the MIT License.