diff --git a/web/src/client/index.js b/web/src/client/index.ts
similarity index 54%
rename from web/src/client/index.js
rename to web/src/client/index.ts
index 5e161ef5f3..7a2d9965cc 100644
--- a/web/src/client/index.js
+++ b/web/src/client/index.ts
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) [2021-2023] SUSE LLC
+ * Copyright (c) [2021-2024] SUSE LLC
  *
  * All Rights Reserved.
  *
@@ -20,28 +20,40 @@
  * find current contact information at www.suse.com.
  */
 
-// @ts-check
-
 import { WSClient } from "./ws";
 
-/**
- * @typedef {object} InstallerClient
- * @property {() => boolean} isConnected - determines whether the client is connected
- * @property {() => boolean} isRecoverable - determines whether the client is recoverable after disconnected
- * @property {(handler: () => void) => (() => void)} onConnect - registers a handler to run
- * @property {(handler: () => void) => (() => void)} onDisconnect - registers a handler to run
- *   when the connection is lost. It returns a function to deregister the
- *   handler.
- * @property {(handler: (any) => void) => (() => void)} onEvent - registers a handler to run on events
- */
+type VoidFn = () => void;
+type BooleanFn = () => boolean;
+type EventHandlerFn = (event: { [key: string]: unknown }) => void;
+
+export type InstallerClient = {
+  /** Whether the client is connected. */
+  isConnected: BooleanFn;
+  /** Whether the client is recoverable after disconnecting. */
+  isRecoverable: BooleanFn;
+  /**
+   * Registers a handler to run when connection is set. It returns a function
+   * for deregistering the handler.
+   */
+  onConnect: (handler: VoidFn) => VoidFn;
+  /**
+   * Registers a handler to run when connection is lost. It returns a function
+   * for deregistering the handler.
+   */
+  onDisconnect: (handler: VoidFn) => VoidFn;
+  /**
+   * Registers a handler to run on events. It returns a function for
+   * deregistering the handler.
+   */
+  onEvent: (handler: EventHandlerFn) => VoidFn;
+};
 
 /**
  * Creates the Agama client
  *
- * @param {URL} url - URL of the HTTP API.
- * @return {InstallerClient}
+ * @param url - URL of the HTTP API.
  */
-const createClient = (url) => {
+const createClient = (url: URL): InstallerClient => {
   url.hash = "";
   url.pathname = url.pathname.concat("api/ws");
   url.protocol = url.protocol === "http:" ? "ws" : "wss";
@@ -53,9 +65,9 @@ const createClient = (url) => {
   return {
     isConnected,
     isRecoverable,
-    onConnect: (handler) => ws.onOpen(handler),
-    onDisconnect: (handler) => ws.onClose(handler),
-    onEvent: (handler) => ws.onEvent(handler),
+    onConnect: (handler: VoidFn) => ws.onOpen(handler),
+    onDisconnect: (handler: VoidFn) => ws.onClose(handler),
+    onEvent: (handler: EventHandlerFn) => ws.onEvent(handler),
   };
 };
 
diff --git a/web/src/client/ws.js b/web/src/client/ws.ts
similarity index 84%
rename from web/src/client/ws.js
rename to web/src/client/ws.ts
index b63c8e2a51..df7e511a08 100644
--- a/web/src/client/ws.js
+++ b/web/src/client/ws.ts
@@ -20,19 +20,13 @@
  * find current contact information at www.suse.com.
  */
 
-// @ts-check
-
-/**
- * @callback RemoveFn
- * @return {void}
- */
+type RemoveFn = () => void;
+type BaseHandlerFn = () => void;
+type EventHandlerFn = (event: { [key: string]: unknown }) => void;
 
 /**
  * Enum for the WebSocket states.
- *
- *
  */
-
 const SocketStates = Object.freeze({
   CONNECTED: 0,
   CONNECTING: 1,
@@ -52,10 +46,25 @@ const ATTEMPT_INTERVAL = 1000;
  * HTTPClient API.
  */
 class WSClient {
+  url: string;
+
+  client: WebSocket;
+
+  handlers: {
+    open: Array<BaseHandlerFn>;
+    close: Array<BaseHandlerFn>;
+    error: Array<BaseHandlerFn>;
+    events: Array<EventHandlerFn>;
+  };
+
+  reconnectAttempts: number;
+
+  timeout: ReturnType<typeof setTimeout>;
+
   /**
-   * @param {URL} url - Websocket URL.
+   * @param  url - Websocket URL.
    */
-  constructor(url) {
+  constructor(url: URL) {
     this.url = url.toString();
 
     this.handlers = {
@@ -126,13 +135,10 @@ class WSClient {
   /**
    * Registers a handler for events.
    *
-   * The handler is executed for all the events. It is up to the callback to
-   * filter the relevant events.
-   *
-   * @param {(object) => void} func - Handler function to register.
-   * @return {RemoveFn}
+   * The handler is executed for all events. It is up to the callback to
+   * filter the relevant ones for it.
    */
-  onEvent(func) {
+  onEvent(func: EventHandlerFn): RemoveFn {
     this.handlers.events.push(func);
     return () => {
       const position = this.handlers.events.indexOf(func);
@@ -144,11 +150,8 @@ class WSClient {
    * Registers a handler for close socket.
    *
    * The handler is executed when the socket is close.
-   *
-   * @param {(object) => void} func - Handler function to register.
-   * @return {RemoveFn}
    */
-  onClose(func) {
+  onClose(func: BaseHandlerFn): RemoveFn {
     this.handlers.close.push(func);
 
     return () => {
@@ -161,10 +164,8 @@ class WSClient {
    * Registers a handler for open socket.
    *
    * The handler is executed when the socket is open.
-   * @param {(object) => void} func - Handler function to register.
-   * @return {RemoveFn}
    */
-  onOpen(func) {
+  onOpen(func: BaseHandlerFn): RemoveFn {
     this.handlers.open.push(func);
 
     return () => {
@@ -177,11 +178,8 @@ class WSClient {
    * Registers a handler for socket errors.
    *
    * The handler is executed when an error is reported by the socket.
-   *
-   * @param {(object) => void} func - Handler function to register.
-   * @return {RemoveFn}
    */
-  onError(func) {
+  onError(func: BaseHandlerFn): RemoveFn {
     this.handlers.error.push(func);
 
     return () => {
@@ -195,9 +193,9 @@ class WSClient {
    *
    * Dispatchs an event by running all the handlers.
    *
-   * @param {object} event - Event object, which is basically a websocket message.
+   * @param event - Event object, which is basically a websocket message.
    */
-  dispatchEvent(event) {
+  dispatchEvent(event: MessageEvent) {
     const eventObject = JSON.parse(event.data);
     this.handlers.events.forEach((f) => f(eventObject));
   }