diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0695d61..49b17fc 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.0-all.zip
diff --git a/library/build.gradle b/library/build.gradle
index f1cfed1..a269b81 100644
--- a/library/build.gradle
+++ b/library/build.gradle
@@ -17,7 +17,7 @@ repositories {
 }
 
 dependencies {
-    compile project(':runtime')
+    compile project(':runtime-lite')
     compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
     compile 'com.github.cretz.pbandk:protoc-gen-kotlin-jvm:0.3.0'
     compile 'com.squareup:kotlinpoet:1.0.1'
diff --git a/library/src/main/kotlin/jp/co/panpanini/MessageGenerator.kt b/library/src/main/kotlin/jp/co/panpanini/MessageGenerator.kt
index a26e019..a93e616 100644
--- a/library/src/main/kotlin/jp/co/panpanini/MessageGenerator.kt
+++ b/library/src/main/kotlin/jp/co/panpanini/MessageGenerator.kt
@@ -5,7 +5,6 @@ import com.improve_future.case_changer.toSnakeCase
 import com.squareup.kotlinpoet.*
 import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
 import pbandk.gen.File
-import java.io.Serializable
 
 class MessageGenerator(private val file: File, private val kotlinTypeMappings: Map<String, String>) {
 
diff --git a/runtime-lite/build.gradle b/runtime-lite/build.gradle
index 32a7ca5..1b74e2a 100644
--- a/runtime-lite/build.gradle
+++ b/runtime-lite/build.gradle
@@ -1,6 +1,4 @@
-apply plugin: 'kotlin'
-apply plugin: 'org.jetbrains.kotlin.jvm'
-apply plugin: 'guru.stefma.artifactorypublish'
+apply plugin: 'kotlin-multiplatform'
 
 sourceCompatibility = 1.8
 
@@ -13,27 +11,26 @@ repositories {
 
 }
 
-dependencies {
-    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
-    compile "com.google.protobuf:protobuf-lite:3.0.1"
-    testCompile group: 'junit', name: 'junit', version: '4.12'
-    testCompile('com.nhaarman.mockitokotlin2:mockito-kotlin:2.1.0')
-    testCompile("org.assertj:assertj-core:3.11.1")
-}
-
-compileKotlin {
-    kotlinOptions.jvmTarget = "1.8"
-}
-compileTestKotlin {
-    kotlinOptions.jvmTarget = "1.8"
-}
+kotlin {
+    targets {
+        jvm()
+    }
 
-artifactoryPublish {
-    groupId = 'jp.co.panpanini'
-    artifactId = 'protok-runtime-lite'
-    publishVersion = versionName()
-    artifactoryUrl = artifactoryUrl
-    artifactoryRepo = artifactoryRepo
-    artifactoryUser = artifactoryUsername
-    artifactoryKey = artifactoryPassword
+    sourceSets {
+        commonMain {}
+        commonTest {}
+        jvmMain {
+            dependencies {
+                implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+                implementation "com.google.protobuf:protobuf-lite:3.0.1"
+            }
+        }
+        jvmTest {
+            dependencies {
+                implementation group: 'junit', name: 'junit', version: '4.12'
+                implementation('com.nhaarman.mockitokotlin2:mockito-kotlin:2.1.0')
+                implementation("org.assertj:assertj-core:3.11.1")
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/runtime-lite/src/main/kotlin/ByteArr.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ByteArr.kt
similarity index 91%
rename from runtime-lite/src/main/kotlin/ByteArr.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ByteArr.kt
index 5783620..cb6de62 100644
--- a/runtime-lite/src/main/kotlin/ByteArr.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ByteArr.kt
@@ -1,7 +1,5 @@
 package jp.co.panpanini
 
-import java.io.Serializable
-
 class ByteArr(val array: ByteArray = ByteArray(0)) : Serializable {
     override fun equals(other: Any?) = other is ByteArr && array.contentEquals(other.array)
     override fun hashCode() = array.contentHashCode()
diff --git a/runtime-lite/src/main/kotlin/Marshaller.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Marshaller.kt
similarity index 100%
rename from runtime-lite/src/main/kotlin/Marshaller.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Marshaller.kt
diff --git a/runtime-lite/src/main/kotlin/Message.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Message.kt
similarity index 77%
rename from runtime-lite/src/main/kotlin/Message.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Message.kt
index d587747..6b04077 100644
--- a/runtime-lite/src/main/kotlin/Message.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Message.kt
@@ -1,17 +1,13 @@
 package jp.co.panpanini
 
-import java.io.InputStream
-import java.io.Serializable
-
 interface Message<T : Message<T>> : Serializable {
     fun protoUnmarshal(u: Unmarshaller): T
     fun protoUnmarshal(arr: ByteArray) = protoUnmarshal(Unmarshaller.fromByteArray(arr))
-    fun protoUnmarshal(inputStream: InputStream) = protoUnmarshal(Unmarshaller(Reader(inputStream.readBytes())))
 
     operator fun plus(other: T?): T
     val protoSize: Int
     fun protoMarshal(m: Marshaller)
-    fun protoMarshal(): ByteArray = Marshaller.allocate(protoSize).also(::protoMarshal).complete()!!
+    fun protoMarshal(): ByteArray = Marshaller.allocate(protoSize).also(::protoMarshal).complete()
 
     interface Companion<T : Message<T>> {
         fun protoUnmarshal(u: Unmarshaller): T
@@ -25,5 +21,4 @@ interface Message<T : Message<T>> : Serializable {
             fun fromValue(value: Int): T
         }
     }
-}
-
+}
\ No newline at end of file
diff --git a/runtime-lite/src/main/kotlin/Reader.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Reader.kt
similarity index 99%
rename from runtime-lite/src/main/kotlin/Reader.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Reader.kt
index 8efdd76..45d4ce5 100644
--- a/runtime-lite/src/main/kotlin/Reader.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Reader.kt
@@ -510,7 +510,7 @@ class Reader(private val byteArray: ByteArray) {
      * nothing is skipped.  Otherwise, returns `true`.
      */
     fun skipField(tag: Int): Boolean {
-        return when (com.google.protobuf.WireFormat.getTagWireType(tag)) {
+        return when (WireFormat.getTagWireType(tag)) {
             WireFormat.WIRETYPE_VARINT -> {
                 skipRawVarint()
                 true
diff --git a/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Serializable.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Serializable.kt
new file mode 100644
index 0000000..7376d5a
--- /dev/null
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Serializable.kt
@@ -0,0 +1,3 @@
+package jp.co.panpanini
+
+expect interface Serializable
diff --git a/runtime-lite/src/main/kotlin/Sizer.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Sizer.kt
similarity index 71%
rename from runtime-lite/src/main/kotlin/Sizer.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Sizer.kt
index 5d8b281..b7d4198 100644
--- a/runtime-lite/src/main/kotlin/Sizer.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Sizer.kt
@@ -1,6 +1,5 @@
 package jp.co.panpanini
 
-import com.google.protobuf.CodedOutputStream
 
 object Sizer {
     fun tagSize(fieldNum: Int): Int {
@@ -48,7 +47,30 @@ object Sizer {
 
     fun int64Size(value: Long) = uInt64Size(value)
 
-    fun uInt64Size(value: Long) = CodedOutputStream.computeUInt64SizeNoTag(value)
+    fun uInt64Size(value: Long): Int {
+         var value = value
+        // handle two popular special cases up front ...
+        if (value and (0L.inv() shl 7) == 0L) {
+            return 1
+        }
+        if (value < 0L) {
+            return 10
+        }
+        // ... leaving us with 8 remaining, which we can divide and conquer
+        var n = 2
+        if (value and (0L.inv() shl 35) != 0L) {
+            n += 4
+            value = value ushr 28
+        }
+        if (value and (0L.inv() shl 21) != 0L) {
+            n += 2
+            value = value ushr 14
+        }
+        if (value and (0L.inv() shl 14) != 0L) {
+            n += 1
+        }
+        return n
+    }
 
     fun bytesSize(value: ByteArray) = uInt32Size(value.size) + value.size
 
@@ -72,7 +94,7 @@ object Sizer {
 
     fun boolSize(value: Boolean) = 1
 
-    fun stringSize(value: String) = CodedOutputStream.computeStringSizeNoTag(value)
+    fun stringSize(value: String) = try { Utf8.encodedLength(value) } catch(e: Exception) { value.toByteArray().size }
 
     private fun Int.zigZagEncode() = (this shl 1) xor (this shr 31)
     private fun Long.zigZagEncode() = (this shl 1) xor (this shr 63)
diff --git a/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ToByteArray.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ToByteArray.kt
new file mode 100644
index 0000000..f51010f
--- /dev/null
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/ToByteArray.kt
@@ -0,0 +1,3 @@
+package jp.co.panpanini
+
+expect fun String.toByteArray(): ByteArray
\ No newline at end of file
diff --git a/runtime-lite/src/main/kotlin/UnknownField.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/UnknownField.kt
similarity index 98%
rename from runtime-lite/src/main/kotlin/UnknownField.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/UnknownField.kt
index a484ef2..4cf8a5d 100644
--- a/runtime-lite/src/main/kotlin/UnknownField.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/UnknownField.kt
@@ -1,8 +1,5 @@
 package jp.co.panpanini
 
-import java.io.Serializable
-
-
 data class UnknownField(val fieldNum: Int, val value: Value) : Serializable {
     constructor(fieldNum: Int, value: Long, fixed: Boolean = false) :
             this(fieldNum, if (fixed) Value.Fixed64(value) else Value.Varint(value))
diff --git a/runtime-lite/src/main/kotlin/Unmarshaller.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Unmarshaller.kt
similarity index 97%
rename from runtime-lite/src/main/kotlin/Unmarshaller.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Unmarshaller.kt
index b262c2c..16a1eb6 100644
--- a/runtime-lite/src/main/kotlin/Unmarshaller.kt
+++ b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Unmarshaller.kt
@@ -54,7 +54,7 @@ class Unmarshaller(private val reader: Reader, private val discardUnknownFields:
         }
         val message = companion.protoUnmarshal(this)
         require(reader.isAtEnd) {
-            "Unable to completely read stream for message ${message::class.java}"
+            "Unable to completely read stream for message ${message::class}"
         }
         reader.popLimit(previousLimit)
         currentUnknownFields = unknownFields
@@ -87,9 +87,9 @@ class Unmarshaller(private val reader: Reader, private val discardUnknownFields:
     }
 
     fun <T: Message<T>> readRepeatedMessage(
-            appendTo: List<T>?,
-            companion: Message.Companion<T>,
-            neverPacked: Boolean
+        appendTo: List<T>?,
+        companion: Message.Companion<T>,
+        neverPacked: Boolean
     ): List<T> {
         return readRepeated(appendTo, neverPacked) {
             readMessage(companion)
diff --git a/runtime-lite/src/main/kotlin/Utf8.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Utf8.kt
similarity index 100%
rename from runtime-lite/src/main/kotlin/Utf8.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Utf8.kt
diff --git a/runtime-lite/src/main/kotlin/Writer.kt b/runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Writer.kt
similarity index 100%
rename from runtime-lite/src/main/kotlin/Writer.kt
rename to runtime-lite/src/commonMain/kotlin/jp/co/panpanini/Writer.kt
diff --git a/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Message.kt b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Message.kt
new file mode 100644
index 0000000..0473b96
--- /dev/null
+++ b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Message.kt
@@ -0,0 +1,7 @@
+package jp.co.panpanini
+
+import java.io.InputStream
+
+fun <T: Message<T>> Message<T>.protoUnmarshal(inputStream: InputStream) = protoUnmarshal(
+   Unmarshaller(Reader(inputStream.readBytes()))
+)
\ No newline at end of file
diff --git a/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Serializable.kt b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Serializable.kt
new file mode 100644
index 0000000..4e6a806
--- /dev/null
+++ b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/Serializable.kt
@@ -0,0 +1,3 @@
+package jp.co.panpanini
+
+actual typealias Serializable = java.io.Serializable
diff --git a/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/toByteArray.kt b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/toByteArray.kt
new file mode 100644
index 0000000..8a45b82
--- /dev/null
+++ b/runtime-lite/src/jvmMain/kotlin/jp/co/panpanini/toByteArray.kt
@@ -0,0 +1,3 @@
+package jp.co.panpanini
+
+actual fun String.toByteArray(): ByteArray = this.toByteArray(Charsets.UTF_8)
\ No newline at end of file
diff --git a/runtime-lite/src/test/kotlin/MarshallerTest.kt b/runtime-lite/src/jvmTest/kotlin/MarshallerTest.kt
similarity index 100%
rename from runtime-lite/src/test/kotlin/MarshallerTest.kt
rename to runtime-lite/src/jvmTest/kotlin/MarshallerTest.kt
diff --git a/runtime-lite/src/test/kotlin/SizerTest.kt b/runtime-lite/src/jvmTest/kotlin/SizerTest.kt
similarity index 100%
rename from runtime-lite/src/test/kotlin/SizerTest.kt
rename to runtime-lite/src/jvmTest/kotlin/SizerTest.kt
diff --git a/runtime-lite/src/test/kotlin/UnmarshallerTest.kt b/runtime-lite/src/jvmTest/kotlin/UnmarshallerTest.kt
similarity index 100%
rename from runtime-lite/src/test/kotlin/UnmarshallerTest.kt
rename to runtime-lite/src/jvmTest/kotlin/UnmarshallerTest.kt
diff --git a/runtime-lite/src/test/kotlin/WriterTest.kt b/runtime-lite/src/jvmTest/kotlin/WriterTest.kt
similarity index 100%
rename from runtime-lite/src/test/kotlin/WriterTest.kt
rename to runtime-lite/src/jvmTest/kotlin/WriterTest.kt
diff --git a/runtime-lite/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker b/runtime-lite/src/jvmTest/resources/mockito-extensions/org.mockito.plugins.MockMaker
similarity index 100%
rename from runtime-lite/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
rename to runtime-lite/src/jvmTest/resources/mockito-extensions/org.mockito.plugins.MockMaker
diff --git a/sample/README.md b/sample/README.md
new file mode 100644
index 0000000..73034f3
--- /dev/null
+++ b/sample/README.md
@@ -0,0 +1,6 @@
+# Sample
+
+A sample project to show how to use the protok library to generate Kotlin classes and how to use the generated classes themselves.
+
+## usage
+Use the gradle task `generateProto` to generate the required Kotlin protocol buffer implementations. This expects protoc to be installed and available on the PATH.
\ No newline at end of file
diff --git a/sample/build.gradle b/sample/build.gradle
new file mode 100644
index 0000000..4a38bf9
--- /dev/null
+++ b/sample/build.gradle
@@ -0,0 +1,29 @@
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm'
+}
+
+version '1.0.0'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib"
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+
+    implementation project(":runtime-lite")
+}
+
+task generateProto(type: Exec) {
+    dependsOn(":library:installDist")
+    commandLine(
+            'protoc',
+            "--plugin=protoc-gen-custom=${rootDir}/library/build/install/protoc-gen-kotlin/bin/protoc-gen-kotlin",
+            "--custom_out=${projectDir}/src/main/kotlin/",
+            "--proto_path=${projectDir}/src/main/proto/",
+            "user.proto"
+    )
+
+}
\ No newline at end of file
diff --git a/sample/src/main/kotlin/Sample.kt b/sample/src/main/kotlin/Sample.kt
new file mode 100644
index 0000000..e902537
--- /dev/null
+++ b/sample/src/main/kotlin/Sample.kt
@@ -0,0 +1,38 @@
+package main.kotlin
+
+class Sample(private val name: String) {
+    companion object {
+        private var LATEST_ID = 1
+    }
+
+    fun generateUser(): User {
+        return User.with {
+            id = LATEST_ID++
+            name = this@Sample.name
+            programingLanguages = listOf(
+                    ProgramingLanguage.with {
+                        name = "Kotlin"
+                        yearsLearning(5)
+                    },
+                    ProgramingLanguage.with {
+                        name = "Java"
+                        yearsLearning(10)
+                    }
+            )
+        }
+    }
+
+}
+
+
+fun main() {
+    val sample = Sample("Panini")
+
+    val user = sample.generateUser()
+
+    println(user)
+    println(user.name)
+    user.programingLanguages.forEach {
+        println("learned ${it.name} for ${it.yearsLearning} years")
+    }
+}
\ No newline at end of file
diff --git a/sample/src/main/proto/user.proto b/sample/src/main/proto/user.proto
new file mode 100644
index 0000000..5cd47b0
--- /dev/null
+++ b/sample/src/main/proto/user.proto
@@ -0,0 +1,14 @@
+syntax = "proto3";
+
+package proto;
+
+message User {
+    int32 id = 1;
+    string name = 2;
+    repeated ProgramingLanguage programingLanguages = 3;
+}
+
+message ProgramingLanguage {
+    string name = 1;
+    int32 yearsLearning = 2;
+}
\ No newline at end of file
diff --git a/settings.gradle b/settings.gradle
index 280728b..e03c584 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1,3 +1,3 @@
-include ':library', ':retrofit-converter', ':runtime', ':runtime-lite', ':retrofit-converter-lite'
+include ':library', ':retrofit-converter', ':runtime', ':runtime-lite', ':retrofit-converter-lite',':sample'
 rootProject.name = 'protok'