diff --git a/kmp-socketio/src/appleMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt b/kmp-socketio/src/appleMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
index e3ed715..ff16810 100644
--- a/kmp-socketio/src/appleMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
+++ b/kmp-socketio/src/appleMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
@@ -1,9 +1,28 @@
 package com.piasy.kmp.socketio.engineio.transports
 
-import io.ktor.client.HttpClientConfig
 import io.ktor.client.HttpClient
+import io.ktor.client.HttpClientConfig
 import io.ktor.client.engine.darwin.Darwin
+import platform.Foundation.NSURLCredential
+import platform.Foundation.NSURLSessionAuthChallengePerformDefaultHandling
+import platform.Foundation.NSURLSessionAuthChallengeUseCredential
+import platform.Foundation.create
+import platform.Foundation.serverTrust
+import platform.Security.SecTrustRef
 
-actual fun httpClient(config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Darwin) {
+actual fun httpClient(trustAllCerts: Boolean, config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Darwin) {
     config(this)
+    engine {
+        if (trustAllCerts) {
+            handleChallenge { session, task, challenge, completionHandler ->
+                val serverTrust: SecTrustRef? = challenge.protectionSpace.serverTrust
+                if (serverTrust != null) {
+                    val credential = NSURLCredential.create(trust = serverTrust)
+                    completionHandler(NSURLSessionAuthChallengeUseCredential.toLong(), credential)
+                } else {
+                    completionHandler(NSURLSessionAuthChallengePerformDefaultHandling.toLong(), null)
+                }
+            }
+        }
+    }
 }
diff --git a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/EngineSocket.kt b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/EngineSocket.kt
index de60b0c..9d12fd3 100644
--- a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/EngineSocket.kt
+++ b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/EngineSocket.kt
@@ -217,6 +217,7 @@ class EngineSocket(
         opts.timestampRequests = options?.timestampRequests ?: opt.timestampRequests
         opts.timestampParam = options?.timestampParam ?: opt.timestampParam
         opts.extraHeaders = opt.extraHeaders
+        opts.trustAllCerts = opt.trustAllCerts
 
         val transport = factory.create(name, opts, scope, rawMessage)
         emit(EVENT_TRANSPORT, transport)
diff --git a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/Transport.kt b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/Transport.kt
index 9ce32a7..51770c4 100644
--- a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/Transport.kt
+++ b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/Transport.kt
@@ -39,6 +39,9 @@ abstract class Transport(
 
         @JvmField
         var extraHeaders: Map<String, List<String>> = emptyMap()
+
+        @JvmField
+        var trustAllCerts: Boolean = false
     }
 
     protected var state = State.INIT
diff --git a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/PollingXHR.kt b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/PollingXHR.kt
index ef0b31e..6978134 100644
--- a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/PollingXHR.kt
+++ b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/PollingXHR.kt
@@ -17,7 +17,7 @@ open class PollingXHR(
     opt: Options,
     scope: CoroutineScope,
     private val ioScope: CoroutineScope = CoroutineScope(Dispatchers.Default),
-    private val factory: HttpClientFactory = DefaultHttpClientFactory,
+    private val factory: HttpClientFactory = DefaultHttpClientFactory(trustAllCerts = opt.trustAllCerts),
     rawMessage: Boolean,
 ) : Transport(opt, scope, NAME, rawMessage) {
     private var polling = false
diff --git a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/WebSocket.kt b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/WebSocket.kt
index e97e325..f24a23c 100644
--- a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/WebSocket.kt
+++ b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/WebSocket.kt
@@ -23,7 +23,7 @@ open class WebSocket(
     opt: Options,
     scope: CoroutineScope,
     private val ioScope: CoroutineScope = CoroutineScope(Dispatchers.Default),
-    private val factory: HttpClientFactory = DefaultHttpClientFactory,
+    private val factory: HttpClientFactory = DefaultHttpClientFactory(trustAllCerts = opt.trustAllCerts),
     rawMessage: Boolean,
 ) : Transport(opt, scope, NAME, rawMessage) {
     private var ws: DefaultClientWebSocketSession? = null
diff --git a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport.kt b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport.kt
index c0869be..c117bb5 100644
--- a/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport.kt
+++ b/kmp-socketio/src/commonMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport.kt
@@ -11,7 +11,7 @@ import io.ktor.client.statement.*
 import io.ktor.http.*
 import kotlinx.coroutines.CoroutineScope
 
-expect fun httpClient(config: HttpClientConfig<*>.() -> Unit = {}): HttpClient
+expect fun httpClient(trustAllCerts: Boolean = false, config: HttpClientConfig<*>.() -> Unit = {}): HttpClient
 
 internal fun putHeaders(
     builder: HeadersBuilder,
@@ -59,8 +59,12 @@ interface HttpClientFactory {
     ): HttpResponse
 }
 
-object DefaultHttpClientFactory : HttpClientFactory {
-    private val wsClient = httpClient {
+class DefaultHttpClientFactory(
+    trustAllCerts: Boolean = false,
+): HttpClientFactory {
+    private val wsClient = httpClient(
+        trustAllCerts = trustAllCerts,
+    ) {
         install(Logging) {
             logger = object : Logger {
                 override fun log(message: String) {
@@ -76,7 +80,9 @@ object DefaultHttpClientFactory : HttpClientFactory {
     // Linux curl engine doesn't work for simultaneous websocket and http request.
     // see https://youtrack.jetbrains.com/issue/KTOR-8259/
     // Use two http client could work around it.
-    private val httpClient: HttpClient = if (!Platform.isLinux) wsClient else httpClient {
+    private val httpClient: HttpClient = if (!Platform.isLinux) wsClient else httpClient(
+        trustAllCerts = trustAllCerts,
+    ) {
         install(Logging) {
             logger = object : Logger {
                 override fun log(message: String) {
diff --git a/kmp-socketio/src/jsMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt b/kmp-socketio/src/jsMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
index 85a59f7..1f79d3c 100644
--- a/kmp-socketio/src/jsMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
+++ b/kmp-socketio/src/jsMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
@@ -4,6 +4,7 @@ import io.ktor.client.HttpClientConfig
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.js.Js
 
-actual fun httpClient(config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Js) {
+actual fun httpClient(trustAllCerts: Boolean, config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Js) {
     config(this)
+    /** Ignore `unsafeClient` variable */
 }
diff --git a/kmp-socketio/src/jvmMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt b/kmp-socketio/src/jvmMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
index c5485c1..251b2ab 100644
--- a/kmp-socketio/src/jvmMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
+++ b/kmp-socketio/src/jvmMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
@@ -3,7 +3,22 @@ package com.piasy.kmp.socketio.engineio.transports
 import io.ktor.client.HttpClientConfig
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.cio.CIO
+import java.security.cert.X509Certificate
+import javax.net.ssl.X509TrustManager
 
-actual fun httpClient(config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(CIO) {
+actual fun httpClient(trustAllCerts: Boolean, config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(CIO) {
     config(this)
+    if (trustAllCerts) {
+        engine {
+            https {
+                trustManager = object: X509TrustManager {
+                    override fun checkClientTrusted(p0: Array<out X509Certificate>?, p1: String?) { }
+
+                    override fun checkServerTrusted(p0: Array<out X509Certificate>?, p1: String?) { }
+
+                    override fun getAcceptedIssuers(): Array<X509Certificate>? = null
+                }
+            }
+        }
+    }
 }
diff --git a/kmp-socketio/src/jvmTest/kotlin/com/piasy/kmp/socketio/engineio/TestUtil.kt b/kmp-socketio/src/jvmTest/kotlin/com/piasy/kmp/socketio/engineio/TestUtil.kt
index 579a3ba..9aecddc 100644
--- a/kmp-socketio/src/jvmTest/kotlin/com/piasy/kmp/socketio/engineio/TestUtil.kt
+++ b/kmp-socketio/src/jvmTest/kotlin/com/piasy/kmp/socketio/engineio/TestUtil.kt
@@ -17,7 +17,7 @@ object TestUtil {
     fun transportFactory() = DefaultTransportFactory
 
     @JvmStatic
-    fun httpFactory() = DefaultHttpClientFactory
+    fun httpFactory() = DefaultHttpClientFactory()
 
     @JvmStatic
     fun getOpt(socket: EngineSocket) = socket.opt
diff --git a/kmp-socketio/src/linuxMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt b/kmp-socketio/src/linuxMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
index 8fcdd99..4ec1c7d 100644
--- a/kmp-socketio/src/linuxMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
+++ b/kmp-socketio/src/linuxMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
@@ -4,6 +4,11 @@ import io.ktor.client.HttpClientConfig
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.curl.Curl
 
-actual fun httpClient(config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Curl) {
+actual fun httpClient(trustAllCerts: Boolean, config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(Curl) {
     config(this)
+    if (trustAllCerts) {
+        engine {
+            sslVerify = false
+        }
+    }
 }
diff --git a/kmp-socketio/src/mingwMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt b/kmp-socketio/src/mingwMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
index 3664d50..7a719d9 100644
--- a/kmp-socketio/src/mingwMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
+++ b/kmp-socketio/src/mingwMain/kotlin/com/piasy/kmp/socketio/engineio/transports/transport_impl.kt
@@ -4,6 +4,11 @@ import io.ktor.client.HttpClientConfig
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.winhttp.WinHttp
 
-actual fun httpClient(config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(WinHttp) {
+actual fun httpClient(trustAllCerts: Boolean, config: HttpClientConfig<*>.() -> Unit): HttpClient = HttpClient(WinHttp) {
     config(this)
+    if (trustAllCerts) {
+        engine {
+            sslVerify = false
+        }
+    }
 }