Build Zoom Video SDK App

/build-zoom-video-sdk-app

Background reference for fully custom video-session products. Prefer plan-zoom-product first when the boundary between Meeting SDK and Video SDK is still unclear.

Build custom video experiences powered by Zoom's infrastructure.

Hard Routing Guardrail (Read First)

• If the user asks for custom real-time video app behavior (topic/session join, custom rendering, attach/detach), route to Video SDK.
• Do not switch to REST meeting endpoints for Video SDK join flows.
• Video SDK does not use Meeting IDs, join_url, or Meeting SDK join payload fields (meetingNumber, passWord).

Meeting SDK vs Video SDK

UI Options (Web)

Video SDK gives you full control over the UI:

Prerequisites

• Zoom Video SDK credentials from Marketplace
• SDK Key and Secret
• Web development environment

Need help with OAuth or signatures? See the [zoom-oauth](../oauth/SKILL.md) skill for authentication flows.

Need pre-join diagnostics on web? Use [probe-sdk](../probe-sdk/SKILL.md) before Video SDK join() to reduce first-minute failures.

Start troubleshooting fast: Use the [5-Minute Runbook](RUNBOOK.md) before deep debugging.

Quick Start (Web)

NPM Usage (Bundler like Vite/Webpack)

import ZoomVideo from '@zoom/videosdk';

const client = ZoomVideo.createClient();
await client.init('en-US', 'Global', { patchJsMedia: true });
await client.join(topic, signature, userName, password);

// IMPORTANT: getMediaStream() ONLY works AFTER join()
const stream = client.getMediaStream();
await stream.startVideo();
await stream.startAudio();

CDN Usage (No Bundler)

WARNING: Ad blockers block `source.zoom.us`. Self-host the SDK to avoid issues.

# Download SDK locally
curl "https://source.zoom.us/videosdk/zoom-video-1.12.0.min.js" -o js/zoom-video-sdk.min.js

<script src="js/zoom-video-sdk.min.js"></script>

// CDN exports as WebVideoSDK, NOT ZoomVideo
// Must use .default property
const ZoomVideo = WebVideoSDK.default;
const client = ZoomVideo.createClient();

await client.init('en-US', 'Global', { patchJsMedia: true });
await client.join(topic, signature, userName, password);

// IMPORTANT: getMediaStream() ONLY works AFTER join()
const stream = client.getMediaStream();
await stream.startVideo();
await stream.startAudio();

ES Module with CDN (Race Condition Fix)

When using <script type="module"> with CDN, SDK may not be loaded yet:

// Wait for SDK to load before using
function waitForSDK(timeout = 10000) {
  return new Promise((resolve, reject) => {
    if (typeof WebVideoSDK !== 'undefined') {
      resolve();
      return;
    }
    const start = Date.now();
    const check = setInterval(() => {
      if (typeof WebVideoSDK !== 'undefined') {
        clearInterval(check);
        resolve();
      } else if (Date.now() - start > timeout) {
        clearInterval(check);
        reject(new Error('SDK failed to load'));
      }
    }, 100);
  });
}

// Usage
await waitForSDK();
const ZoomVideo = WebVideoSDK.default;
const client = ZoomVideo.createClient();

SDK Lifecycle (CRITICAL ORDER)

The SDK has a strict lifecycle. Violating it causes silent failures.

1. Create client:     client = ZoomVideo.createClient()
2. Initialize:        await client.init('en-US', 'Global', options)
3. Join session:      await client.join(topic, signature, userName, password)
4. Get stream:        stream = client.getMediaStream()  ← ONLY AFTER JOIN
5. Start media:       await stream.startVideo() / await stream.startAudio()

Common Mistake (Silent Failure):

// ❌ WRONG: Getting stream before joining
const client = ZoomVideo.createClient();
await client.init('en-US', 'Global');
const stream = client.getMediaStream();  // Returns undefined!
await client.join(...);

// ✅ CORRECT: Get stream after joining
const client = ZoomVideo.createClient();
await client.init('en-US', 'Global');
await client.join(...);
const stream = client.getMediaStream();  // Works!

Video Rendering (Event-Driven)

The SDK is event-driven. You must listen for events and render videos accordingly.

Use attachVideo() NOT renderVideo()

import { VideoQuality } from '@zoom/videosdk';

// Start your camera
await stream.startVideo();

// Attach video - returns element to append to DOM
const element = await stream.attachVideo(userId, VideoQuality.Video_360P);
container.appendChild(element);

// Detach when done
await stream.detachVideo(userId);

Required Events

// When other participant's video turns on/off
client.on('peer-video-state-change', async (payload) => {
  const { action, userId } = payload;
  if (action === 'Start') {
    const el = await stream.attachVideo(userId, VideoQuality.Video_360P);
    container.appendChild(el);
  } else {
    await stream.detachVideo(userId);
  }
});

// When participants join/leave
client.on('user-added', (payload) => { /* check bVideoOn */ });
client.on('user-removed', (payload) => { stream.detachVideo(payload.userId); });

See web/references/web.md for complete event handling patterns.

Key Concepts

Session Creation Model

Important: Video SDK sessions are created just-in-time, not in advance.

How Sessions Work

1. No pre-creation needed: Sessions don't exist until someone joins
2. Topic = Session ID: Any participants joining with the same topic string join the same session
3. First join creates it: The session is created when the first participant joins
4. No meeting ID: There's no numeric meeting ID like in Zoom Meetings

// Session is created on-the-fly when first user joins
// Any string can be the topic - it becomes the session identifier
await client.join('my-custom-session-123', signature, 'User Name');

// Other participants join the SAME session by using the SAME topic
await client.join('my-custom-session-123', signature, 'Another User');

Signature Endpoint Setup

The signature endpoint must be accessible from your frontend without CORS issues.

Option 1: Same-Origin Proxy (Recommended)

# Nginx config
location /api/ {
    proxy_pass http://YOUR_BACKEND_HOST:3005/api/;
    proxy_http_version 1.1;
    proxy_set_header Host $host;
}

// Frontend uses relative URL (same origin)
const response = await fetch('/api/signature', { ... });

Option 2: CORS Configuration

// Express.js backend
const cors = require('cors');
app.use(cors({
  origin: ['https://your-domain.com'],
  credentials: true
}));

WARNING: Mixed content (HTTPS page → HTTP API) will be blocked by browsers.

Use Cases