# Use tokens (/en/realtime-media/voice/build/set-up-token-authentication/use-tokens/electron) > For AI agents: see the complete documentation index at [llms.txt](/llms.txt). To protect your business, it is best practice to authenticate every client that joins a channel. This guide explains how to fetch an authentication token from your token server, use it to join a channel, and renew the token when it expires. ## Understand the tech [#understand-the-tech] When a user attempts to connect to an Agora channel, your app retrieves a token from the token server in your security infrastructure. Your app then sends this token to Agora SDRTN® for authentication. Agora SDRTN® reads the information stored in the token to validate the request. The following figure shows the call flow you implement to create step-up-authentication with Agora Voice Calling: **Token authentication flow** ![token authentication flow](https://assets-docs.agora.io/images/video-sdk/token-authentication.svg) ## Prerequisites [#prerequisites-5] Before starting, ensure that you have: * Implemented the [Quickstart](../index.mdx) in your project. * Deployed a token server using either of the following guides: * [Deploy a token server](deploy-token-server.mdx) * [Deploy a middleware server](middleware-token-server.md) ## Implement basic authentication [#implement-basic-authentication-5] This section shows you how to implement basic authentication by acquiring a token and using it to join a channel. ### Use a token to join a channel [#use-a-token-to-join-a-channel-5] This section shows you how to integrate token authentication in your app. 1. Open the [SDK quickstart](../index.mdx) project you created earlier. 2. In `renderer.js` replace the contents with the following: **Sample code for basic authentication** ```dart const { createAgoraRtcEngine, VideoMirrorModeType, VideoSourceType, RenderModeType, ChannelProfileType, ClientRoleType, } = require("agora-electron-sdk"); let rtcEngine; let localVideoContainer; let remoteVideoContainer; let isJoined = false; const EventHandles = { // Listen to local user joining channel events onJoinChannelSuccess: ({ channelId, localUid }, elapsed) => { console.log('Successfully joined the channel：' + channelId); isJoined = true; // After local users join the channel, set the local video window rtcEngine.setupLocalVideo({ sourceType: VideoSourceType.VideoSourceCameraPrimary, view: localVideoContainer, mirrorMode: VideoMirrorModeType.VideoMirrorModeDisabled, renderMode: RenderModeType.RenderModeFit, }); }, onLeaveChannel: ({ channelId, localUid }, stats) => { console.log('Successfully left the channel:' + channelId); isJoined = false; }, // Listen to remote user join event onUserJoined: ({ channelId, localUid }, remoteUid, elapsed) => { console.log('Remote user ' + remoteUid + ' 已加入'); // Listen to remote user join event rtcEngine.setupRemoteVideoEx( { sourceType: VideoSourceType.VideoSourceRemote, uid: remoteUid, view: remoteVideoContainer, mirrorMode: VideoMirrorModeType.VideoMirrorModeDisabled, renderMode: RenderModeType.RenderModeFit, }, { channelId }, ); }, // Listen for the token expiration event onTokenPrivilegeWillExpire: ({ channelId, localUid }, token) => { console.log('token ' + token + '即将过期'); // Obtain a new token from the server fetchToken(channelId, localUid, ClientRoleType.ClientRoleBroadcaster) }, // Listen for the token expired event onRequestToken: ({ channelId, localUid }) => { console.log('token expired'); token = '' } }; // Send a token request to the token server function fetchToken(channelName, uid, role) { //Token server URL example: http://12.123.1.123:8082/fetch_rtc_token const url = '/fetch_rtc_token'; const body = JSON.stringify({ uid, ChannelName: channelName, role }); fetch(url, { method: 'POST', body, }) .then((res) => res.json()) .then((res) => { console.log('token ' + res.token); if (+res.code === 200) { if (isJoined) { rtcEngine.renewToken(res.token) } else { rtcEngine.joinChannel(res.token, channelName, uid, { clientRoleType: role }) } } return res; }); } window.onload = () => { const os = require("os"); const path = require("path"); // Fill in your app ID const APPID = ""; // Fill in the channel name const channel = "Test"; localVideoContainer = document.getElementById("join-channel-local-video"); remoteVideoContainer = document.getElementById("join-channel-remote-video"); const sdkLogPath = path.resolve(os.homedir(), "./test.log"); // Create an RtcEngine instance rtcEngine = createAgoraRtcEngine(); // Initialize the RtcEngine instance rtcEngine.initialize({ appId: APPID, logConfig: { filePath: sdkLogPath } }); // Register event handler rtcEngine.registerEventHandler(EventHandles); //Set the channel profile to live broadcast rtcEngine.setChannelProfile(ChannelProfileType.ChannelProfileLiveBroadcasting); // Set the user role, for host use ClientRoleBroadcaster, for audience use ClientRoleAudience rtcEngine.setClientRole(ClientRoleType.ClientRoleBroadcaster); // Enable the video module rtcEngine.enableVideo(); // Enable camera preview rtcEngine.startPreview(); // Use the token to join a channel // You need to specify the user ID yourself and ensure its uniqueness within the channel fetchToken(channel, 123456, ClientRoleType.ClientRoleBroadcaster); }; ``` Replace `` with your app ID, which must be consistent with the app ID you specified in the server configuration. Update `` with the host URL and port of the local Golang server you have deployed. For example `99.9.9.99:8082`. The sample code implements the following logic: * Calls `joinChannel` to join a channel using the user ID, the channel name, and a token you obtain from the server. The user ID and channel name you specify must be consistent with the values you used to generate the token. * The SDK triggers an `onTokenPrivilegeWillExpire` callback 30 seconds before the token expires. After receiving the callback, you obtain a new token from the server and call `renewToken` to pass the newly generated token to the SDK. * If the token expires, the SDK triggers an `onRequestToken` callback. After receiving the callback, obtain a new token from the server and call `joinChannel` with the new token to rejoin the channel. Build and run the project on the local device, the app performs the following operations: * Obtains a token from your token server. * Joins the channel. * Automatically renews the token when it is about to expire. The user ID and channel name used to join a channel must be consistent with the values used to generate the token. ## Reference [#reference-5] This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product. ### API reference [#api-reference-4] * [renewToken](https://api-ref.agora.io/en/voice-sdk/electron/4.x/API/class_irtcengine.html#api_irtcengine_renewtoken) * [onTokenPrivilegeWillExpire](https://api-ref.agora.io/en/voice-sdk/electron/4.x/API/class_irtcengineeventhandler.html#callback_irtcengineeventhandler_ontokenprivilegewillexpire) * [onRequestToken](https://api-ref.agora.io/en/voice-sdk/electron/4.x/API/class_irtcengineeventhandler.html#callback_irtcengineeventhandler_onrequesttoken)