diff --git a/ktor-http/api/ktor-http.api b/ktor-http/api/ktor-http.api
index f369eca9d6a..3b3da432dff 100644
--- a/ktor-http/api/ktor-http.api
+++ b/ktor-http/api/ktor-http.api
@@ -262,7 +262,7 @@ public final class io/ktor/http/ContentTypesKt {
 	public static final fun withCharsetIfNeeded (Lio/ktor/http/ContentType;Ljava/nio/charset/Charset;)Lio/ktor/http/ContentType;
 }
 
-public final class io/ktor/http/Cookie {
+public final class io/ktor/http/Cookie : java/io/Serializable {
 	public static final field Companion Lio/ktor/http/Cookie$Companion;
 	public fun <init> (Ljava/lang/String;Ljava/lang/String;Lio/ktor/http/CookieEncoding;Ljava/lang/Integer;Lio/ktor/util/date/GMTDate;Ljava/lang/String;Ljava/lang/String;ZZLjava/util/Map;)V
 	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lio/ktor/http/CookieEncoding;Ljava/lang/Integer;Lio/ktor/util/date/GMTDate;Ljava/lang/String;Ljava/lang/String;ZZLjava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
@@ -966,7 +966,7 @@ public final class io/ktor/http/URLParserKt {
 	public static final fun takeFrom (Lio/ktor/http/URLBuilder;Ljava/lang/String;)Lio/ktor/http/URLBuilder;
 }
 
-public final class io/ktor/http/URLProtocol {
+public final class io/ktor/http/URLProtocol : java/io/Serializable {
 	public static final field Companion Lio/ktor/http/URLProtocol$Companion;
 	public fun <init> (Ljava/lang/String;I)V
 	public final fun component1 ()Ljava/lang/String;
@@ -1026,7 +1026,7 @@ public final class io/ktor/http/UnsafeHeaderException : java/lang/IllegalArgumen
 	public fun <init> (Ljava/lang/String;)V
 }
 
-public final class io/ktor/http/Url {
+public final class io/ktor/http/Url : java/io/Serializable {
 	public static final field Companion Lio/ktor/http/Url$Companion;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getEncodedFragment ()Ljava/lang/String;
@@ -1053,6 +1053,7 @@ public final class io/ktor/http/Url {
 }
 
 public final class io/ktor/http/Url$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
 }
 
 public final class io/ktor/http/UrlKt {
@@ -1060,6 +1061,15 @@ public final class io/ktor/http/UrlKt {
 	public static final fun getProtocolWithAuthority (Lio/ktor/http/Url;)Ljava/lang/String;
 }
 
+public final class io/ktor/http/UrlSerializer : kotlinx/serialization/KSerializer {
+	public fun <init> ()V
+	public fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/ktor/http/Url;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/ktor/http/Url;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+}
+
 public final class io/ktor/http/auth/AuthScheme {
 	public static final field Basic Ljava/lang/String;
 	public static final field Bearer Ljava/lang/String;
diff --git a/ktor-http/api/ktor-http.klib.api b/ktor-http/api/ktor-http.klib.api
index 7bd6b70711b..7ab441b73c7 100644
--- a/ktor-http/api/ktor-http.klib.api
+++ b/ktor-http/api/ktor-http.klib.api
@@ -573,7 +573,7 @@ final class io.ktor.http/ContentType : io.ktor.http/HeaderValueWithParameters {
     }
 }
 
-final class io.ktor.http/Cookie { // io.ktor.http/Cookie|null[0]
+final class io.ktor.http/Cookie : io.ktor.utils.io/JvmSerializable { // io.ktor.http/Cookie|null[0]
     constructor <init>(kotlin/String, kotlin/String, io.ktor.http/CookieEncoding = ..., kotlin/Int? = ..., io.ktor.util.date/GMTDate? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Boolean = ..., kotlin/Boolean = ..., kotlin.collections/Map<kotlin/String, kotlin/String?> = ...) // io.ktor.http/Cookie.<init>|<init>(kotlin.String;kotlin.String;io.ktor.http.CookieEncoding;kotlin.Int?;io.ktor.util.date.GMTDate?;kotlin.String?;kotlin.String?;kotlin.Boolean;kotlin.Boolean;kotlin.collections.Map<kotlin.String,kotlin.String?>){}[0]
 
     final val domain // io.ktor.http/Cookie.domain|{}domain[0]
@@ -1048,7 +1048,7 @@ final class io.ktor.http/URLParserException : kotlin/IllegalStateException { //
     constructor <init>(kotlin/String, kotlin/Throwable) // io.ktor.http/URLParserException.<init>|<init>(kotlin.String;kotlin.Throwable){}[0]
 }
 
-final class io.ktor.http/URLProtocol { // io.ktor.http/URLProtocol|null[0]
+final class io.ktor.http/URLProtocol : io.ktor.utils.io/JvmSerializable { // io.ktor.http/URLProtocol|null[0]
     constructor <init>(kotlin/String, kotlin/Int) // io.ktor.http/URLProtocol.<init>|<init>(kotlin.String;kotlin.Int){}[0]
 
     final val defaultPort // io.ktor.http/URLProtocol.defaultPort|{}defaultPort[0]
@@ -1085,7 +1085,7 @@ final class io.ktor.http/UnsafeHeaderException : kotlin/IllegalArgumentException
     constructor <init>(kotlin/String) // io.ktor.http/UnsafeHeaderException.<init>|<init>(kotlin.String){}[0]
 }
 
-final class io.ktor.http/Url { // io.ktor.http/Url|null[0]
+final class io.ktor.http/Url : io.ktor.utils.io/JvmSerializable { // io.ktor.http/Url|null[0]
     final val encodedFragment // io.ktor.http/Url.encodedFragment|{}encodedFragment[0]
         final fun <get-encodedFragment>(): kotlin/String // io.ktor.http/Url.encodedFragment.<get-encodedFragment>|<get-encodedFragment>(){}[0]
     final val encodedPassword // io.ktor.http/Url.encodedPassword|{}encodedPassword[0]
@@ -1129,7 +1129,19 @@ final class io.ktor.http/Url { // io.ktor.http/Url|null[0]
     final fun hashCode(): kotlin/Int // io.ktor.http/Url.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // io.ktor.http/Url.toString|toString(){}[0]
 
-    final object Companion // io.ktor.http/Url.Companion|null[0]
+    final object Companion { // io.ktor.http/Url.Companion|null[0]
+        final fun serializer(): kotlinx.serialization/KSerializer<io.ktor.http/Url> // io.ktor.http/Url.Companion.serializer|serializer(){}[0]
+    }
+}
+
+final class io.ktor.http/UrlSerializer : kotlinx.serialization/KSerializer<io.ktor.http/Url> { // io.ktor.http/UrlSerializer|null[0]
+    constructor <init>() // io.ktor.http/UrlSerializer.<init>|<init>(){}[0]
+
+    final val descriptor // io.ktor.http/UrlSerializer.descriptor|{}descriptor[0]
+        final fun <get-descriptor>(): kotlinx.serialization.descriptors/SerialDescriptor // io.ktor.http/UrlSerializer.descriptor.<get-descriptor>|<get-descriptor>(){}[0]
+
+    final fun deserialize(kotlinx.serialization.encoding/Decoder): io.ktor.http/Url // io.ktor.http/UrlSerializer.deserialize|deserialize(kotlinx.serialization.encoding.Decoder){}[0]
+    final fun serialize(kotlinx.serialization.encoding/Encoder, io.ktor.http/Url) // io.ktor.http/UrlSerializer.serialize|serialize(kotlinx.serialization.encoding.Encoder;io.ktor.http.Url){}[0]
 }
 
 sealed class io.ktor.http.auth/HttpAuthHeader { // io.ktor.http.auth/HttpAuthHeader|null[0]
diff --git a/ktor-http/build.gradle.kts b/ktor-http/build.gradle.kts
index 0ec58b576f7..bb98a0ec6c1 100644
--- a/ktor-http/build.gradle.kts
+++ b/ktor-http/build.gradle.kts
@@ -14,5 +14,12 @@ kotlin {
                 api(libs.kotlinx.serialization.core)
             }
         }
+        jvmTest {
+            dependencies {
+                implementation(project(":ktor-shared:ktor-junit"))
+                implementation(project(":ktor-shared:ktor-serialization:ktor-serialization-kotlinx"))
+                implementation(project(":ktor-shared:ktor-serialization:ktor-serialization-kotlinx:ktor-serialization-kotlinx-json"))
+            }
+        }
     }
 }
diff --git a/ktor-http/common/src/io/ktor/http/Cookie.kt b/ktor-http/common/src/io/ktor/http/Cookie.kt
index 4db6b279f8e..8470f6565df 100644
--- a/ktor-http/common/src/io/ktor/http/Cookie.kt
+++ b/ktor-http/common/src/io/ktor/http/Cookie.kt
@@ -6,6 +6,7 @@ package io.ktor.http
 
 import io.ktor.util.*
 import io.ktor.util.date.*
+import io.ktor.utils.io.*
 import kotlinx.serialization.*
 import kotlin.jvm.*
 
@@ -37,7 +38,17 @@ public data class Cookie(
     val secure: Boolean = false,
     val httpOnly: Boolean = false,
     val extensions: Map<String, String?> = emptyMap()
-)
+) : JvmSerializable {
+    private fun writeReplace(): Any = JvmSerializerReplacement(CookieJvmSerializer, this)
+}
+
+internal object CookieJvmSerializer : JvmSerializer<Cookie> {
+    override fun jvmSerialize(value: Cookie): ByteArray =
+        renderSetCookieHeader(value).encodeToByteArray()
+
+    override fun jvmDeserialize(value: ByteArray): Cookie =
+        parseServerSetCookieHeader(value.decodeToString())
+}
 
 /**
  * Cooke encoding strategy
diff --git a/ktor-http/common/src/io/ktor/http/URLProtocol.kt b/ktor-http/common/src/io/ktor/http/URLProtocol.kt
index 5095eb6fd4c..513e6287014 100644
--- a/ktor-http/common/src/io/ktor/http/URLProtocol.kt
+++ b/ktor-http/common/src/io/ktor/http/URLProtocol.kt
@@ -5,13 +5,14 @@
 package io.ktor.http
 
 import io.ktor.util.*
+import io.ktor.utils.io.*
 
 /**
  * Represents URL protocol
  * @property name of protocol (schema)
  * @property defaultPort default port for protocol or `-1` if not known
  */
-public data class URLProtocol(val name: String, val defaultPort: Int) {
+public data class URLProtocol(val name: String, val defaultPort: Int) : JvmSerializable {
     init {
         require(name.all { it.isLowerCase() }) { "All characters should be lower case" }
     }
diff --git a/ktor-http/common/src/io/ktor/http/Url.kt b/ktor-http/common/src/io/ktor/http/Url.kt
index d50c96d8c4a..60c94e0aeec 100644
--- a/ktor-http/common/src/io/ktor/http/Url.kt
+++ b/ktor-http/common/src/io/ktor/http/Url.kt
@@ -4,6 +4,11 @@
 
 package io.ktor.http
 
+import io.ktor.utils.io.*
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.encoding.*
+
 /**
  * Represents an immutable URL
  *
@@ -18,6 +23,7 @@ package io.ktor.http
  * @property password password part of URL
  * @property trailingQuery keep trailing question character even if there are no query parameters
  */
+@Serializable(with = UrlSerializer::class)
 public class Url internal constructor(
     protocol: URLProtocol?,
     public val host: String,
@@ -29,7 +35,7 @@ public class Url internal constructor(
     public val password: String?,
     public val trailingQuery: Boolean,
     private val urlString: String
-) {
+) : JvmSerializable {
     init {
         require(specifiedPort in 0..65535) {
             "Port must be between 0 and 65535, or $DEFAULT_PORT if not set. Provided: $specifiedPort"
@@ -222,6 +228,8 @@ public class Url internal constructor(
         return urlString.hashCode()
     }
 
+    private fun writeReplace(): Any = JvmSerializerReplacement(UrlJvmSerializer, this)
+
     public companion object
 }
 
@@ -254,3 +262,22 @@ internal val Url.encodedUserAndPassword: String
     get() = buildString {
         appendUserAndPassword(encodedUser, encodedPassword)
     }
+
+public class UrlSerializer : KSerializer<Url> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("Url", PrimitiveKind.STRING)
+
+    override fun deserialize(decoder: Decoder): Url =
+        Url(decoder.decodeString())
+
+    override fun serialize(encoder: Encoder, value: Url) {
+        encoder.encodeString(value.toString())
+    }
+}
+
+internal object UrlJvmSerializer : JvmSerializer<Url> {
+    override fun jvmSerialize(value: Url): ByteArray =
+        value.toString().encodeToByteArray()
+
+    override fun jvmDeserialize(value: ByteArray): Url =
+        Url(value.decodeToString())
+}
diff --git a/ktor-http/jvm/test/io/ktor/tests/http/SerializableTest.kt b/ktor-http/jvm/test/io/ktor/tests/http/SerializableTest.kt
new file mode 100644
index 00000000000..bc2e21fc599
--- /dev/null
+++ b/ktor-http/jvm/test/io/ktor/tests/http/SerializableTest.kt
@@ -0,0 +1,24 @@
+// ktlint-disable filename
+/*
+ * Copyright 2014-2019 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package io.ktor.tests.http
+
+import io.ktor.http.*
+import io.ktor.junit.*
+import kotlin.test.*
+
+class SerializableTest {
+    @Test
+    fun urlTest() {
+        val url = Url("https://localhost/path?key=value#fragment")
+        assertEquals(url, assertSerializable(url))
+    }
+
+    @Test
+    fun cookieTest() {
+        val cookie = Cookie("key", "value")
+        assertEquals(cookie, assertSerializable(cookie))
+    }
+}
diff --git a/ktor-io/api/ktor-io.api b/ktor-io/api/ktor-io.api
index 8cb92a34138..147672b699b 100644
--- a/ktor-io/api/ktor-io.api
+++ b/ktor-io/api/ktor-io.api
@@ -209,6 +209,17 @@ public final class io/ktor/utils/io/CountedByteWriteChannelKt {
 	public static final fun counted (Lio/ktor/utils/io/ByteWriteChannel;)Lio/ktor/utils/io/CountedByteWriteChannel;
 }
 
+public final class io/ktor/utils/io/DefaultJvmSerializerReplacement : java/io/Externalizable {
+	public static final field Companion Lio/ktor/utils/io/DefaultJvmSerializerReplacement$Companion;
+	public fun <init> ()V
+	public fun <init> (Lio/ktor/utils/io/JvmSerializer;Ljava/lang/Object;)V
+	public fun readExternal (Ljava/io/ObjectInput;)V
+	public fun writeExternal (Ljava/io/ObjectOutput;)V
+}
+
+public final class io/ktor/utils/io/DefaultJvmSerializerReplacement$Companion {
+}
+
 public final class io/ktor/utils/io/DeprecationKt {
 	public static final fun readText (Lkotlinx/io/Source;)Ljava/lang/String;
 	public static final fun release (Lkotlinx/io/Sink;)V
@@ -217,6 +228,15 @@ public final class io/ktor/utils/io/DeprecationKt {
 public abstract interface annotation class io/ktor/utils/io/InternalAPI : java/lang/annotation/Annotation {
 }
 
+public final class io/ktor/utils/io/JvmSerializable_jvmKt {
+	public static final fun JvmSerializerReplacement (Lio/ktor/utils/io/JvmSerializer;Ljava/lang/Object;)Ljava/lang/Object;
+}
+
+public abstract interface class io/ktor/utils/io/JvmSerializer : java/io/Serializable {
+	public abstract fun jvmDeserialize ([B)Ljava/lang/Object;
+	public abstract fun jvmSerialize (Ljava/lang/Object;)[B
+}
+
 public abstract interface annotation class io/ktor/utils/io/KtorDsl : java/lang/annotation/Annotation {
 }
 
diff --git a/ktor-io/api/ktor-io.klib.api b/ktor-io/api/ktor-io.klib.api
index cba7dc34d45..b56b03ef723 100644
--- a/ktor-io/api/ktor-io.klib.api
+++ b/ktor-io/api/ktor-io.klib.api
@@ -53,6 +53,11 @@ abstract interface <#A: kotlin/Any> io.ktor.utils.io.pool/ObjectPool : kotlin/Au
     open fun close() // io.ktor.utils.io.pool/ObjectPool.close|close(){}[0]
 }
 
+abstract interface <#A: kotlin/Any?> io.ktor.utils.io/JvmSerializer : io.ktor.utils.io/JvmSerializable { // io.ktor.utils.io/JvmSerializer|null[0]
+    abstract fun jvmDeserialize(kotlin/ByteArray): #A // io.ktor.utils.io/JvmSerializer.jvmDeserialize|jvmDeserialize(kotlin.ByteArray){}[0]
+    abstract fun jvmSerialize(#A): kotlin/ByteArray // io.ktor.utils.io/JvmSerializer.jvmSerialize|jvmSerialize(1:0){}[0]
+}
+
 abstract interface io.ktor.utils.io.core/Closeable : kotlin/AutoCloseable { // io.ktor.utils.io.core/Closeable|null[0]
     abstract fun close() // io.ktor.utils.io.core/Closeable.close|close(){}[0]
 }
@@ -97,6 +102,8 @@ abstract interface io.ktor.utils.io/ChannelJob { // io.ktor.utils.io/ChannelJob|
         abstract fun <get-job>(): kotlinx.coroutines/Job // io.ktor.utils.io/ChannelJob.job.<get-job>|<get-job>(){}[0]
 }
 
+abstract interface io.ktor.utils.io/JvmSerializable // io.ktor.utils.io/JvmSerializable|null[0]
+
 abstract class <#A: kotlin/Any> io.ktor.utils.io.pool/DefaultPool : io.ktor.utils.io.pool/ObjectPool<#A> { // io.ktor.utils.io.pool/DefaultPool|null[0]
     constructor <init>(kotlin/Int) // io.ktor.utils.io.pool/DefaultPool.<init>|<init>(kotlin.Int){}[0]
 
@@ -399,6 +406,7 @@ final fun (kotlinx.io/Source).io.ktor.utils.io.core/readTextExactCharacters(kotl
 final fun (kotlinx.io/Source).io.ktor.utils.io.core/release() // io.ktor.utils.io.core/release|release@kotlinx.io.Source(){}[0]
 final fun (kotlinx.io/Source).io.ktor.utils.io.core/takeWhile(kotlin/Function1<kotlinx.io/Buffer, kotlin/Boolean>) // io.ktor.utils.io.core/takeWhile|takeWhile@kotlinx.io.Source(kotlin.Function1<kotlinx.io.Buffer,kotlin.Boolean>){}[0]
 final fun (kotlinx.io/Source).io.ktor.utils.io/readText(): kotlin/String // io.ktor.utils.io/readText|readText@kotlinx.io.Source(){}[0]
+final fun <#A: kotlin/Any> io.ktor.utils.io/JvmSerializerReplacement(io.ktor.utils.io/JvmSerializer<#A>, #A): kotlin/Any // io.ktor.utils.io/JvmSerializerReplacement|JvmSerializerReplacement(io.ktor.utils.io.JvmSerializer<0:0>;0:0){0§<kotlin.Any>}[0]
 final fun <#A: kotlin/Any?> (kotlinx.io/Sink).io.ktor.utils.io.core/preview(kotlin/Function1<kotlinx.io/Source, #A>): #A // io.ktor.utils.io.core/preview|preview@kotlinx.io.Sink(kotlin.Function1<kotlinx.io.Source,0:0>){0§<kotlin.Any?>}[0]
 final fun <#A: kotlin/Any?> (kotlinx.io/Source).io.ktor.utils.io.core/preview(kotlin/Function1<kotlinx.io/Source, #A>): #A // io.ktor.utils.io.core/preview|preview@kotlinx.io.Source(kotlin.Function1<kotlinx.io.Source,0:0>){0§<kotlin.Any?>}[0]
 final fun <#A: kotlin/Any?> io.ktor.utils.io.core/withMemory(kotlin/Int, kotlin/Function1<kotlin/ByteArray, #A>): #A // io.ktor.utils.io.core/withMemory|withMemory(kotlin.Int;kotlin.Function1<kotlin.ByteArray,0:0>){0§<kotlin.Any?>}[0]
diff --git a/ktor-io/common/src/io/ktor/utils/io/JvmSerializable.kt b/ktor-io/common/src/io/ktor/utils/io/JvmSerializable.kt
new file mode 100644
index 00000000000..490fdef56c8
--- /dev/null
+++ b/ktor-io/common/src/io/ktor/utils/io/JvmSerializable.kt
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package io.ktor.utils.io
+
+public expect interface JvmSerializable
+
+public interface JvmSerializer<T> : JvmSerializable {
+    public fun jvmSerialize(value: T): ByteArray
+    public fun jvmDeserialize(value: ByteArray): T
+}
+
+public expect fun <T : Any> JvmSerializerReplacement(serializer: JvmSerializer<T>, value: T): Any
+
+internal object DummyJvmSimpleSerializerReplacement
diff --git a/ktor-io/jsAndWasmShared/src/io/ktor/utils/io/JvmSerializable.jsAndWasmShared.kt b/ktor-io/jsAndWasmShared/src/io/ktor/utils/io/JvmSerializable.jsAndWasmShared.kt
new file mode 100644
index 00000000000..5fcedcdd9b3
--- /dev/null
+++ b/ktor-io/jsAndWasmShared/src/io/ktor/utils/io/JvmSerializable.jsAndWasmShared.kt
@@ -0,0 +1,11 @@
+/*
+ * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package io.ktor.utils.io
+
+/** Alias for `java.io.Serializable` on JVM. Empty interface otherwise. */
+public actual interface JvmSerializable
+
+public actual fun <T : Any> JvmSerializerReplacement(serializer: JvmSerializer<T>, value: T): Any =
+    DummyJvmSimpleSerializerReplacement
diff --git a/ktor-io/jvm/src/io/ktor/utils/io/JvmSerializable.jvm.kt b/ktor-io/jvm/src/io/ktor/utils/io/JvmSerializable.jvm.kt
new file mode 100644
index 00000000000..875bf5b8edb
--- /dev/null
+++ b/ktor-io/jvm/src/io/ktor/utils/io/JvmSerializable.jvm.kt
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package io.ktor.utils.io
+
+import java.io.*
+
+public actual typealias JvmSerializable = Serializable
+
+@Suppress("UNCHECKED_CAST")
+public actual fun <T : Any> JvmSerializerReplacement(serializer: JvmSerializer<T>, value: T): Any =
+    DefaultJvmSerializerReplacement(serializer, value)
+
+@PublishedApi // IMPORTANT: changing the class name would result in serialization incompatibility
+internal class DefaultJvmSerializerReplacement<T : Any>(
+    private var serializer: JvmSerializer<T>?,
+    private var value: T?
+) : Externalizable {
+    constructor() : this(null, null)
+
+    override fun writeExternal(out: ObjectOutput) {
+        out.writeObject(serializer)
+        out.writeObject(serializer!!.jvmSerialize(value!!))
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    override fun readExternal(`in`: ObjectInput) {
+        serializer = `in`.readObject() as JvmSerializer<T>
+        value = serializer!!.jvmDeserialize(`in`.readObject() as ByteArray)
+    }
+
+    private fun readResolve(): Any =
+        value!!
+
+    companion object {
+        private const val serialVersionUID: Long = 0L
+    }
+}
diff --git a/ktor-io/posix/src/io/ktor/utils/io/JvmSerializable.posix.kt b/ktor-io/posix/src/io/ktor/utils/io/JvmSerializable.posix.kt
new file mode 100644
index 00000000000..5fcedcdd9b3
--- /dev/null
+++ b/ktor-io/posix/src/io/ktor/utils/io/JvmSerializable.posix.kt
@@ -0,0 +1,11 @@
+/*
+ * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package io.ktor.utils.io
+
+/** Alias for `java.io.Serializable` on JVM. Empty interface otherwise. */
+public actual interface JvmSerializable
+
+public actual fun <T : Any> JvmSerializerReplacement(serializer: JvmSerializer<T>, value: T): Any =
+    DummyJvmSimpleSerializerReplacement
diff --git a/ktor-shared/ktor-junit/jvm/src/io/ktor/junit/Assertions.kt b/ktor-shared/ktor-junit/jvm/src/io/ktor/junit/Assertions.kt
index f5e0d07b1e8..f3857c1e453 100644
--- a/ktor-shared/ktor-junit/jvm/src/io/ktor/junit/Assertions.kt
+++ b/ktor-shared/ktor-junit/jvm/src/io/ktor/junit/Assertions.kt
@@ -4,6 +4,8 @@
 
 package io.ktor.junit
 
+import java.io.*
+
 /**
  * Convenience function for asserting on all elements of a collection.
  */
@@ -29,3 +31,10 @@ fun <T> assertAll(collection: Iterable<T>, assertion: (T) -> Unit) {
         }
     )
 }
+
+inline fun <reified T : Any> assertSerializable(obj: T): T {
+    val encoded = ByteArrayOutputStream().also {
+        ObjectOutputStream(it).writeObject(obj)
+    }.toByteArray()
+    return ObjectInputStream(encoded.inputStream()).readObject() as T
+}