diff --git a/CHANGELOG.md b/CHANGELOG.md
index 473a95a5c6..608414806b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ __All the `tgbotapi.extensions.*` packages have been removed__
     * Constructor of `UnknownInlineKeyboardButton` is not internal and can be created with any `json` ([#563](https://github.com/InsanusMokrassar/TelegramBotAPI/issues/563))
     * All the interfaces from `dev.inmo.tgbotapi.types.files.abstracts` have been replaced to `dev.inmo.tgbotapi.types.files` and converted to sealed ([#550](https://github.com/InsanusMokrassar/TelegramBotAPI/issues/550))
     * `PassportFile` has been replaced to `dev.inmo.tgbotapi.types.files`
+* `WebApps`:
+    * Created 🎉
 
 ## 0.38.13
 
diff --git a/settings.gradle b/settings.gradle
index bd0430c7c5..6cf2139f0b 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -17,4 +17,5 @@ include ":tgbotapi.utils"
 include ":tgbotapi.behaviour_builder"
 include ":tgbotapi.behaviour_builder.fsm"
 include ":tgbotapi"
+include ":tgbotapi.webapps"
 include ":docs"
diff --git a/tgbotapi.webapps/build.gradle b/tgbotapi.webapps/build.gradle
new file mode 100644
index 0000000000..257fcf8f02
--- /dev/null
+++ b/tgbotapi.webapps/build.gradle
@@ -0,0 +1,49 @@
+buildscript {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
+    }
+}
+
+plugins {
+    id "org.jetbrains.kotlin.multiplatform"
+    id "org.jetbrains.kotlin.plugin.serialization"
+}
+
+project.version = "$library_version"
+project.group = "$library_group"
+project.description = "Web App bindings for the Telegram Web Apps API"
+
+apply from: "../publish.gradle"
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
+
+kotlin {
+    js(IR) {
+        browser()
+        nodejs()
+    }
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation kotlin('stdlib')
+                api project(":tgbotapi.core")
+            }
+        }
+    }
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
+}
+
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ColorScheme.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ColorScheme.kt
new file mode 100644
index 0000000000..2b30dec7da
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ColorScheme.kt
@@ -0,0 +1,6 @@
+package dev.inmo.tgbotapi.webapps
+
+enum class ColorScheme {
+    LIGHT,
+    DARK
+}
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt
new file mode 100644
index 0000000000..f56acf10d2
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventHandler.kt
@@ -0,0 +1,4 @@
+package dev.inmo.tgbotapi.webapps
+
+typealias EventHandler = WebApp.() -> Unit
+typealias ViewportChangedEventHandler = WebApp.(Boolean) -> Unit
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventType.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventType.kt
new file mode 100644
index 0000000000..1771966db3
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/EventType.kt
@@ -0,0 +1,7 @@
+package dev.inmo.tgbotapi.webapps
+
+sealed class EventType(val typeName: String) {
+    object ThemeChanged : EventType("themeChanged")
+    object ViewportChanged : EventType("viewportChanged")
+    object MainButtonClicked : EventType("mainButtonClicked")
+}
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/MainButton.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/MainButton.kt
new file mode 100644
index 0000000000..3fabb5a2e7
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/MainButton.kt
@@ -0,0 +1,55 @@
+package dev.inmo.tgbotapi.webapps
+
+import kotlin.js.Json
+import kotlin.js.json
+
+external class MainButton {
+    val text: String
+    fun setText(text: String): MainButton
+
+    var color: String
+    var textColor: String
+
+    val isVisible: Boolean
+    fun show(): MainButton
+    fun hide(): MainButton
+
+    val isActive: Boolean
+    fun enable(): MainButton
+    fun disable(): MainButton
+
+    val isProgressVisible: Boolean
+    fun showProgress(leaveActive: Boolean = definedExternally): MainButton
+    fun hideProgress(): MainButton
+
+    internal fun onClick(eventHandler: () -> Unit): MainButton
+
+    internal fun setParams(params: Json): MainButton
+}
+
+data class MainButtonParams(
+    val text: String? = null,
+    val color: String? = null,
+    val textColor: String? = null,
+    val isActive: Boolean? = null,
+    val isVisible: Boolean? = null
+)
+
+fun MainButton.onClick(eventHandler: EventHandler) = onClick {
+    val that = js("this").unsafeCast<WebApp>()
+    that.eventHandler()
+}
+
+fun MainButton.setParams(params: MainButtonParams) = setParams(
+    json(
+        *listOfNotNull(
+            params.text ?.let { "text" to params.text },
+            params.color ?.let { "color" to params.color },
+            params.textColor ?.let { "text_color" to params.textColor },
+            params.isActive ?.let { "is_active" to params.isActive },
+            params.isVisible ?.let { "is_visible" to params.isVisible },
+        ).toTypedArray()
+    )
+)
+
+
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/Telegram.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/Telegram.kt
new file mode 100644
index 0000000000..3666fc481b
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/Telegram.kt
@@ -0,0 +1,10 @@
+package dev.inmo.tgbotapi.webapps
+
+import org.w3c.dom.Window
+
+external interface Telegram {
+    val WebApp: WebApp
+}
+
+val Window.Telegram
+    get() = asDynamic().Telegram.unsafeCast<Telegram>()
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ThemeParams.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ThemeParams.kt
new file mode 100644
index 0000000000..a8db758c55
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/ThemeParams.kt
@@ -0,0 +1,16 @@
+package dev.inmo.tgbotapi.webapps
+
+external interface ThemeParams {
+    @JsName("bg_color")
+    val backgroundColor: String?
+    @JsName("text_color")
+    val textColor: String?
+    @JsName("hint_color")
+    val hintColor: String?
+    @JsName("link_color")
+    val linkColor: String?
+    @JsName("button_color")
+    val buttonColor: String?
+    @JsName("button_text_color")
+    val buttonTextColor: String?
+}
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt
new file mode 100644
index 0000000000..8a21b744a7
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebApp.kt
@@ -0,0 +1,75 @@
+package dev.inmo.tgbotapi.webapps
+
+external class WebApp {
+    val initData: String
+    val initDataUnsafe: WebAppInitData
+
+    @JsName("colorScheme")
+    val colorSchemeRaw: String
+    val themeParams: ThemeParams
+
+    val isExpanded: Boolean
+    val viewportHeight: Float
+    val viewportStableHeight: Float
+
+    @JsName("MainButton")
+    val mainButton: MainButton
+
+    internal fun onEvent(type: String, callback: () -> Unit)
+    @JsName("onEvent")
+    internal fun onEventWithBoolean(type: String, callback: (Boolean) -> Unit)
+
+    fun offEvent(type: String, callback: () -> Unit)
+    @JsName("offEvent")
+    fun offEventWithBoolean(type: String, callback: (Boolean) -> Unit)
+
+    fun sendData(data: String)
+
+    fun ready()
+    fun expand()
+    fun close()
+}
+
+val WebApp.colorScheme: ColorScheme
+    get() = when (colorSchemeRaw) {
+        "light" -> ColorScheme.LIGHT
+        "dark" -> ColorScheme.DARK
+        else -> ColorScheme.LIGHT
+    }
+
+/**
+ * @return The callback which should be used in case you want to turn off events handling
+ */
+fun WebApp.onEvent(type: EventType, eventHandler: EventHandler) = {
+    eventHandler(js("this").unsafeCast<WebApp>())
+}.also {
+    onEvent(
+        type.typeName,
+        callback = it
+    )
+}
+
+/**
+ * @return The callback which should be used in case you want to turn off events handling
+ */
+fun WebApp.onEvent(type: EventType.ViewportChanged, eventHandler: ViewportChangedEventHandler) = { it: Boolean ->
+    eventHandler(js("this").unsafeCast<WebApp>(), it)
+}.also {
+    onEventWithBoolean(
+        type.typeName,
+        callback = it
+    )
+}
+
+/**
+ * @return The callback which should be used in case you want to turn off events handling
+ */
+fun WebApp.onThemeChanged(eventHandler: EventHandler) = onEvent(EventType.ThemeChanged, eventHandler)
+/**
+ * @return The callback which should be used in case you want to turn off events handling
+ */
+fun WebApp.onMainButtonClicked(eventHandler: EventHandler) = onEvent(EventType.MainButtonClicked, eventHandler)
+/**
+ * @return The callback which should be used in case you want to turn off events handling
+ */
+fun WebApp.onViewportChanged(eventHandler: ViewportChangedEventHandler) = onEvent(EventType.ViewportChanged, eventHandler)
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppInitData.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppInitData.kt
new file mode 100644
index 0000000000..a00181ab91
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppInitData.kt
@@ -0,0 +1,19 @@
+package dev.inmo.tgbotapi.webapps
+
+import dev.inmo.tgbotapi.types.MilliSeconds
+import dev.inmo.tgbotapi.types.WebAppQueryId
+
+external interface WebAppInitData {
+    val queryId: WebAppQueryId?
+
+    val user: WebAppUser?
+    val receiver: WebAppUser?
+
+    @JsName("start_param")
+    val startParam: String?
+
+    @JsName("auth_date")
+    val authDate: MilliSeconds
+
+    val hash: String
+}
diff --git a/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppUser.kt b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppUser.kt
new file mode 100644
index 0000000000..a192b422ff
--- /dev/null
+++ b/tgbotapi.webapps/src/jsMain/kotlin/dev/inmo/tgbotapi/webapps/WebAppUser.kt
@@ -0,0 +1,37 @@
+package dev.inmo.tgbotapi.webapps
+
+import dev.inmo.micro_utils.language_codes.IetfLanguageCode
+import dev.inmo.tgbotapi.types.*
+
+external interface WebAppUser {
+    val id: Identifier
+    @JsName(isBotField)
+    val isBot: Boolean?
+    @JsName(firstNameField)
+    val firstName: String
+    @JsName(lastNameField)
+    val lastName: String?
+    @JsName(usernameField)
+    val username: String?
+    @JsName(languageCodeField)
+    val languageCode: String?
+    @JsName(photoUrlField)
+    val photoUrl: String?
+}
+
+fun WebAppUser.asUser() = if (isBot == true) {
+    CommonBot(
+        UserId(id),
+        username ?.let(::Username) ?: error("Username is absent for bot, but must exists"),
+        firstName,
+        lastName ?: ""
+    )
+} else {
+    CommonUser(
+        UserId(id),
+        firstName,
+        lastName ?: "",
+        username ?.let(::Username),
+        languageCode ?.let(::IetfLanguageCode)
+    )
+}