diff --git a/lazer/sdk/js/README.md b/lazer/sdk/js/README.md
index 65e587c6c9..d5cae31334 100644
--- a/lazer/sdk/js/README.md
+++ b/lazer/sdk/js/README.md
@@ -1,4 +1,58 @@
-# pyth-lazer-sdk - Readme
+# Pyth Lazer JavaScript SDK
+
+A JavaScript/TypeScript SDK for connecting to the Pyth Lazer service, supporting both Node and browser environments.
+
+
+## Quick Start
+Install with:
+```sh
+npm install @pythnetwork/pyth-lazer-sdk
+```
+
+Connect to Lazer and process the messages:
+```javascript
+import { PythLazerClient } from '@pythnetwork/pyth-lazer-sdk';
+
+const client = await PythLazerClient.create({
+  urls: ['wss://your-lazer-endpoint/v1/stream'],
+  token: 'your-access-token',
+  numConnections: 3
+});
+
+// Register an event handler for each price update message.
+client.addMessageListener((message) => {
+  console.log('Received:', message);
+});
+
+// Subscribe to a feed. You can call subscribe() multiple times. 
+client.subscribe({
+  type: "subscribe",
+  subscriptionId: 1,
+  priceFeedIds: [1, 2],
+  properties: ["price"],
+  formats: ["solana"],
+  deliveryFormat: "binary",
+  channel: "fixed_rate@200ms",
+  parsed: false,
+  jsonBinaryEncoding: "base64",
+});
+```
+
+For a full demo, run the example in `examples/index.ts` with:
+```
+pnpm run example
+```
+### Build locally
+
+Build ESM and CJS packages with:
+
+```sh
+pnpm turbo build -F @pythnetwork/pyth-lazer-sdk
+```
+
+## API Reference
+
+For detailed API documentation, see the [TypeDoc documentation](docs/typedoc/).
 
 ## Contributing & Development
 
diff --git a/lazer/sdk/js/examples/index.ts b/lazer/sdk/js/examples/index.ts
index f6170b542e..e86febb4cb 100644
--- a/lazer/sdk/js/examples/index.ts
+++ b/lazer/sdk/js/examples/index.ts
@@ -4,7 +4,7 @@
 import { PythLazerClient } from "../src/index.js";
 
 // Ignore debug messages
-console.debug = () => {};
+console.debug = () => { };
 
 const client = await PythLazerClient.create({
   urls: [
diff --git a/lazer/sdk/js/package.json b/lazer/sdk/js/package.json
index 6c412d5281..7f209389df 100644
--- a/lazer/sdk/js/package.json
+++ b/lazer/sdk/js/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@pythnetwork/pyth-lazer-sdk",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "Pyth Lazer SDK",
   "publishConfig": {
     "access": "public"
diff --git a/lazer/sdk/js/src/socket/websocket-pool.ts b/lazer/sdk/js/src/socket/websocket-pool.ts
index 6e57811c0c..23a6b0c701 100644
--- a/lazer/sdk/js/src/socket/websocket-pool.ts
+++ b/lazer/sdk/js/src/socket/websocket-pool.ts
@@ -1,3 +1,5 @@
+import type { ClientRequestArgs } from "node:http";
+
 import TTLCache from "@isaacs/ttlcache";
 import type { ErrorEvent } from "isomorphic-ws";
 import WebSocket from "isomorphic-ws";
@@ -8,6 +10,84 @@ import type { Request, Response } from "../protocol.js";
 import type { ResilientWebSocketConfig } from "./resilient-websocket.js";
 import { ResilientWebSocket } from "./resilient-websocket.js";
 
+/**
+ * Browser global interface for proper typing
+ */
+type BrowserGlobal = {
+  window?: {
+    document?: unknown;
+  };
+  importScripts?: (...urls: string[]) => void;
+}
+
+/**
+ * Detects if the code is running in a regular DOM or Web Worker context.
+ * @returns true if running in a DOM or Web Worker context, false if running in Node.js
+ */
+function isBrowser(): boolean {
+  try {
+    // Check for browser's window object (DOM context)
+    if (typeof globalThis !== "undefined") {
+      const global = globalThis as BrowserGlobal;
+      if (global.window?.document) {
+        return true;
+      }
+
+      // Check for Web Worker context (has importScripts but no window)
+      if (typeof global.importScripts === "function" && !global.window) {
+        return true;
+      }
+    }
+
+    // Node.js environment
+    return false;
+  } catch {
+    // If any error occurs, assume Node.js environment
+    return false;
+  }
+}
+
+/**
+ * Adds authentication to either the URL as a query parameter or as an Authorization header.
+ * 
+ * Browsers don't support custom headers for WebSocket connections, so if a browser is detected,
+ * the token is added as a query parameter instead. Else, the token is added as an Authorization header.
+ * 
+ * @param url - The WebSocket URL
+ * @param token - The authentication token
+ * @param wsOptions - Existing WebSocket options
+ * @returns Object containing the modified endpoint and wsOptions
+ */
+function addAuthentication(
+  url: string,
+  token: string,
+  wsOptions: WebSocket.ClientOptions | ClientRequestArgs | undefined = {}
+): { endpoint: string; wsOptions: WebSocket.ClientOptions | ClientRequestArgs | undefined } {
+  if (isBrowser()) {
+    // Browser: Add token as query parameter
+    const urlObj = new URL(url);
+    urlObj.searchParams.set("ACCESS_TOKEN", token);
+
+    // For browsers, filter out wsOptions since headers aren't supported
+    return {
+      endpoint: urlObj.toString(),
+      wsOptions: undefined,
+    };
+  } else {
+    // Node.js: Add Authorization header
+    return {
+      endpoint: url,
+      wsOptions: {
+        ...wsOptions,
+        headers: {
+          ...(wsOptions.headers as Record<string, string> | undefined),
+          Authorization: `Bearer ${token}`,
+        },
+      },
+    };
+  }
+}
+
 const DEFAULT_NUM_CONNECTIONS = 4;
 
 export type WebSocketPoolConfig = {
@@ -63,15 +143,17 @@ export class WebSocketPool {
       if (!url) {
         throw new Error(`URLs must not be null or empty`);
       }
-      const wsOptions = {
-        ...config.rwsConfig?.wsOptions,
-        headers: {
-          Authorization: `Bearer ${config.token}`,
-        },
-      };
+
+      // Apply authentication based on environment (browser vs Node.js)
+      const { endpoint, wsOptions } = addAuthentication(
+        url,
+        config.token,
+        config.rwsConfig?.wsOptions
+      );
+
       const rws = new ResilientWebSocket({
         ...config.rwsConfig,
-        endpoint: url,
+        endpoint,
         wsOptions,
         logger,
       });