diff --git a/build.gradle.kts b/build.gradle.kts
index 199593397..2a8af91ff 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -23,6 +23,10 @@ buildscript {
     }
 }
 
+plugins {
+    id("org.jetbrains.dokka") version "0.10.1" apply false
+}
+
 runCatching {
     val keyProps = Properties().apply {
         file("local.properties").takeIf { it.exists() }?.inputStream()?.use { load(it) }
diff --git a/mirai-core/build.gradle.kts b/mirai-core/build.gradle.kts
index fc9b8a63e..40cc278ac 100644
--- a/mirai-core/build.gradle.kts
+++ b/mirai-core/build.gradle.kts
@@ -4,6 +4,7 @@ plugins {
     kotlin("multiplatform")
     id("kotlinx-atomicfu")
     id("kotlinx-serialization")
+    id("org.jetbrains.dokka")
     `maven-publish`
     id("com.jfrog.bintray") version "1.8.4-jetbrains-3"
 }
@@ -145,5 +146,15 @@ kotlin {
 //tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
 //    kotlinOptions.jvmTarget = "1.8"
 //}
+tasks {
+    val dokka by getting(org.jetbrains.dokka.gradle.DokkaTask::class) {
+        outputFormat = "html"
+        outputDirectory = "$buildDir/dokka"
+    }
+    val dokkaMarkdown by creating(org.jetbrains.dokka.gradle.DokkaTask::class) {
+        outputFormat = "markdown"
+        outputDirectory = "$buildDir/dokka-markdown"
+    }
+}
 
 apply(from = rootProject.file("gradle/publish.gradle"))
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Json.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Json.kt
deleted file mode 100644
index 739bd907e..000000000
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Json.kt
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright 2020 Mamoe Technologies and contributors.
- *
- * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
- * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
- *
- * https://github.com/mamoe/mirai/blob/master/LICENSE
- */
-
-package net.mamoe.mirai.message.data
-
-import net.mamoe.mirai.utils.MiraiExperimentalAPI
-import net.mamoe.mirai.utils.SinceMirai
-
-/**
- * Json 消息.
- *
- * @see LightApp 一些消息实际上是 [LightApp]
- */
-@SinceMirai("0.27.0")
-@OptIn(MiraiExperimentalAPI::class)
-class JsonMessage(override val content: String) : RichMessage {
-    companion object Key : Message.Key<JsonMessage>
-
-    // serviceId = 1
-    override fun toString(): String = content
-}
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/LightApp.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/LightApp.kt
deleted file mode 100644
index 7c7277d67..000000000
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/LightApp.kt
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Copyright 2020 Mamoe Technologies and contributors.
- *
- * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
- * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
- *
- * https://github.com/mamoe/mirai/blob/master/LICENSE
- */
-
-package net.mamoe.mirai.message.data
-
-import net.mamoe.mirai.utils.MiraiExperimentalAPI
-import net.mamoe.mirai.utils.SinceMirai
-
-/**
- * 小程序分享, 如音乐分享
- */
-@OptIn(MiraiExperimentalAPI::class)
-@SinceMirai("0.27.0")
-class LightApp constructor(override val content: String) : RichMessage {
-    companion object Key : Message.Key<LightApp>
-
-    override fun toString(): String = content
-}
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/RichMessage.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/RichMessage.kt
index af967da8e..844f67744 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/RichMessage.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/RichMessage.kt
@@ -9,7 +9,10 @@
 
 package net.mamoe.mirai.message.data
 
+import net.mamoe.mirai.utils.MiraiExperimentalAPI
 import net.mamoe.mirai.utils.SinceMirai
+import kotlin.jvm.JvmOverloads
+import kotlin.jvm.JvmSynthetic
 
 /**
  * XML 消息等富文本消息
@@ -18,9 +21,169 @@ import net.mamoe.mirai.utils.SinceMirai
  * @see JsonMessage
  * @see LightApp
  */
+// not using sealed class for customized implementations
 @SinceMirai("0.27.0")
 interface RichMessage : MessageContent {
-    companion object Key : Message.Key<RichMessage>
+
+    @SinceMirai("0.30.0")
+    companion object Templates : Message.Key<RichMessage> {
+
+        @MiraiExperimentalAPI
+        @SinceMirai("0.30.0")
+        fun share(url: String, title: String? = null, content: String? = null, coverUrl: String? = null): XmlMessage =
+            buildXMLMessage {
+                templateId = 12345
+                serviceId = 1
+                action = "web"
+                brief = "[分享] " + (title.orEmpty())
+                this.url = url
+                item {
+                    layout = 2
+                    if (coverUrl != null) {
+                        picture(coverUrl)
+                    }
+                    if (title != null) {
+                        title(title)
+                    }
+                    if (content != null) {
+                        summary(content)
+                    }
+                }
+            }
+    }
 
     val content: String
-}
\ No newline at end of file
+
+    override val length: Int get() = content.length
+    override fun get(index: Int): Char = content[index]
+    override fun subSequence(startIndex: Int, endIndex: Int): CharSequence = content.subSequence(startIndex, endIndex)
+    override fun compareTo(other: String): Int = content.compareTo(other)
+}
+
+/**
+ * Json 消息.
+ *
+ * @see LightApp 一些消息实际上是 [LightApp]
+ */
+@SinceMirai("0.27.0")
+@OptIn(MiraiExperimentalAPI::class)
+class JsonMessage(override val content: String) : RichMessage {
+    companion object Key : Message.Key<JsonMessage>
+
+    // serviceId = 1
+    override fun toString(): String = content
+}
+
+/**
+ * 小程序分享, 如音乐分享
+ */
+@OptIn(MiraiExperimentalAPI::class)
+@SinceMirai("0.27.0")
+class LightApp constructor(override val content: String) : RichMessage {
+
+    companion object Key : Message.Key<LightApp>
+
+    override fun toString(): String = content
+}
+
+
+/**
+ * XML 消息, 如分享, 卡片等.
+ *
+ * @see buildXMLMessage
+ */
+@SinceMirai("0.27.0")
+@OptIn(MiraiExperimentalAPI::class)
+class XmlMessage constructor(override val content: String) : RichMessage {
+    companion object Key : Message.Key<XmlMessage>
+
+    // override val serviceId: Int get() = 60
+
+    override fun toString(): String = content
+}
+
+/**
+ * 构造一条 XML 消息
+ */
+@JvmSynthetic
+@SinceMirai("0.27.0")
+@MiraiExperimentalAPI
+inline fun buildXMLMessage(block: @XMLDsl XMLMessageBuilder.() -> Unit): XmlMessage =
+    XmlMessage(XMLMessageBuilder().apply(block).text)
+
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.TYPE)
+@DslMarker
+annotation class XMLDsl
+
+@Suppress("MemberVisibilityCanBePrivate")
+@XMLDsl
+class XMLMessageBuilder(
+    var templateId: Int = 1,
+    var serviceId: Int = 1,
+    var action: String = "plugin",
+    /**
+     * 一般为点击这条消息后跳转的链接
+     */
+    var actionData: String = "",
+    /**
+     * 摘要, 在官方客户端内消息列表中显示
+     */
+    var brief: String = "",
+    var flag: Int = 3,
+    var url: String = "", // TODO: 2019/12/3 unknown
+    var sourceName: String = "",
+    var sourceIconURL: String = ""
+) {
+    @PublishedApi
+    internal val builder: StringBuilder = StringBuilder()
+
+    val text: String
+        get() = "<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>" +
+                "<msg templateID='$templateId' serviceID='$serviceId' action='$action' actionData='$actionData' brief='$brief' flag='$flag' url='$url'>" +
+                builder.toString() +
+                "<source name='$sourceName' icon='$sourceIconURL'/>" +
+                "</msg>"
+
+    @JvmOverloads
+    @XMLDsl
+    inline fun item(bg: Int = 0, layout: Int = 4, block: @XMLDsl ItemBuilder.() -> Unit) {
+        builder.append(ItemBuilder(bg, layout).apply(block).text)
+    }
+
+    fun source(name: String, iconURL: String = "") {
+        sourceName = name
+        sourceIconURL = iconURL
+    }
+
+    @SinceMirai("0.27.0")
+    @XMLDsl
+    class ItemBuilder @PublishedApi internal constructor(
+        var bg: Int = 0,
+        var layout: Int = 4
+    ) {
+        @PublishedApi
+        internal val builder: StringBuilder = StringBuilder()
+        val text: String get() = "<item bg='$bg' layout='$layout'>$builder</item>"
+
+        fun summary(text: String, color: String = "#000000") {
+            this.builder.append("<summary color='$color'>$text</summary>")
+        }
+
+        fun title(text: String, size: Int = 25, color: String = "#000000") {
+            this.builder.append("<title size='$size' color='$color'>$text</title>")
+        }
+
+        fun picture(coverUrl: String) {
+            this.builder.append("<picture cover='$coverUrl'/>")
+        }
+    }
+}
+
+@Deprecated(
+    "for source compatibility",
+    replaceWith = ReplaceWith("RichMessage.Templates", "net.mamoe.mirai.message.data.RichMessage"),
+    level = DeprecationLevel.ERROR
+)
+@Suppress("unused")
+// in bytecode it's public
+internal typealias XmlMessageHelper = RichMessage.Templates
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
deleted file mode 100644
index 1a69474aa..000000000
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
- * Copyright 2020 Mamoe Technologies and contributors.
- *
- * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
- * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
- *
- * https://github.com/mamoe/mirai/blob/master/LICENSE
- */
-
-@file:JvmMultifileClass
-@file:JvmName("MessageUtils")
-
-@file:Suppress("MemberVisibilityCanBePrivate")
-
-package net.mamoe.mirai.message.data
-
-import net.mamoe.mirai.utils.MiraiExperimentalAPI
-import net.mamoe.mirai.utils.SinceMirai
-import kotlin.jvm.JvmMultifileClass
-import kotlin.jvm.JvmName
-import kotlin.jvm.JvmSynthetic
-
-/**
- * XML 消息, 如分享, 卡片等.
- *
- * @see buildXMLMessage
- */
-@SinceMirai("0.27.0")
-@OptIn(MiraiExperimentalAPI::class)
-class XmlMessage constructor(override val content: String) : RichMessage {
-    companion object Key : Message.Key<XmlMessage>
-
-    // override val serviceId: Int get() = 60
-
-    override fun toString(): String = content
-}
-
-/**
- * 构造一条 XML 消息
- */
-@JvmSynthetic
-@SinceMirai("0.27.0")
-@MiraiExperimentalAPI
-inline fun buildXMLMessage(block: @XMLDsl XMLMessageBuilder.() -> Unit): XmlMessage =
-    XmlMessage(XMLMessageBuilder().apply(block).text)
-
-@SinceMirai("0.27.0")
-@XMLDsl
-class ItemBuilder(
-    var bg: Int = 0,
-    var layout: Int = 4
-) {
-    @PublishedApi
-    internal val builder: StringBuilder = StringBuilder()
-    val text: String get() = "<item bg='$bg' layout='$layout'>$builder</item>"
-
-    fun summary(text: String, color: String = "#000000") {
-        this.builder.append("<summary color='$color'>$text</summary>")
-    }
-
-    fun title(text: String, size: Int = 25, color: String = "#000000") {
-        this.builder.append("<title size='$size' color='$color'>$text</title>")
-    }
-
-    fun picture(coverUrl: String) {
-        this.builder.append("<picture cover='$coverUrl'/>")
-    }
-}
-
-@XMLDsl
-class XMLMessageBuilder(
-    var templateId: Int = 1,
-    var serviceId: Int = 1,
-    var action: String = "plugin",
-    /**
-     * 一般为点击这条消息后跳转的链接
-     */
-    var actionData: String = "",
-    /**
-     * 摘要, 在官方客户端内消息列表中显示
-     */
-    var brief: String = "",
-    var flag: Int = 3,
-    var url: String = "", // TODO: 2019/12/3 unknown
-    var sourceName: String = "",
-    var sourceIconURL: String = ""
-) {
-    @PublishedApi
-    internal val builder: StringBuilder = StringBuilder()
-
-    val text: String
-        get() = "<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>" +
-                "<msg templateID='$templateId' serviceID='$serviceId' action='$action' actionData='$actionData' brief='$brief' flag='$flag' url='$url'>" +
-                builder.toString() +
-                "<source name='$sourceName' icon='$sourceIconURL'/>" +
-                "</msg>"
-
-    @XMLDsl
-    fun item(block: @XMLDsl ItemBuilder.() -> Unit) {
-        builder.append(ItemBuilder().apply(block).text)
-    }
-
-    fun source(name: String, iconURL: String = "") {
-        sourceName = name
-        sourceIconURL = iconURL
-    }
-}
-
-@MiraiExperimentalAPI
-object XmlMessageHelper {
-    fun share(u: String, title: String?, content: String?, image: String?) = buildXMLMessage {
-        templateId = 12345
-        serviceId = 1
-        action = "web"
-        brief = "[分享] " + (title ?: "")
-        url = u
-        item {
-            layout = 2
-            if (image != null) {
-                picture(image)
-            }
-            if (title != null) {
-                title(title)
-            }
-            if (content != null) {
-                summary(content)
-            }
-        }
-    }
-}
-
-@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.TYPE)
-@DslMarker
-annotation class XMLDsl