name: build-zoom-video-sdk-app description: Reference skill for Zoom Video SDK. Use after routing to a custom-session workflow when the user needs full control over the video experience rather than an actual Zoom meeting. triggers:

• "custom video"
• "video sdk"
• "build video app"
• "video session"
• "video chat"
• "video call"
• "video conferencing"
• "custom video ui"
• "twitter spaces"
• "clubhouse alternative"
• "audio-only room"
• "screen sharing"
• "virtual background"
• "native video sdk"

/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

BYOS (Bring Your Own Storage)

Video SDK feature - Zoom saves cloud recordings directly to your Amazon S3 bucket. No downloading required.

Official docs: https://developers.zoom.us/docs/build/storage/

Prerequisites:

• Video SDK account with Cloud Recording add-on (Universal Credit includes this)
• AWS S3 bucket

Authentication options:

1. AWS Access Key - simpler setup
2. Cross Account Access - more secure (IAM role assumption)

S3 path structure:

Buckets/{bucketName}/cmr/byos/{YYYY}/{MM}/{DD}/{GUID}/cmr_byos/

Key benefits:

• Zero download bandwidth costs
• Direct storage during recording
• Config-only setup (no webhook/download code needed)

Setup location: Developer Portal → Account Settings → General → Communications Content Storage Location

See [../general/use-cases/video-sdk-bring-your-own-storage.md](../general/use-cases/video-sdk-bring-your-own-storage.md) for complete setup guide.

Detailed References

UI & Components

• [references/ui-toolkit.md](references/ui-toolkit.md) - Pre-built UI components (Web)
• [references/triage-intake.md](references/triage-intake.md) - What to ask first (turn vague reports into answers)
• [references/session-lifecycle.md](references/session-lifecycle.md) - Correct API ordering + event-driven rendering
• [references/licensing-and-entitlements.md](references/licensing-and-entitlements.md) - License/admin prerequisites
• [references/token-contract-test-spec.md](references/token-contract-test-spec.md) - Shared backend token contract and cross-platform smoke test

Platform Guides

• [references/authorization.md](references/authorization.md) - Video SDK JWT generation
• [web/SKILL.md](web/SKILL.md) - Web Video SDK (JavaScript/TypeScript)
• [web/SKILL.md](web/SKILL.md) - Complete documentation navigation
• [web/examples/react-hooks.md](web/examples/react-hooks.md) - Official React hooks library
• [web/examples/framework-integrations.md](web/examples/framework-integrations.md) - Next.js, Vue/Nuxt patterns
• [react-native/SKILL.md](react-native/SKILL.md) - React Native Video SDK (mobile wrapper, helper/event architecture)
• [react-native/SKILL.md](react-native/SKILL.md) - React Native documentation navigation
• [react-native/examples/session-join-pattern.md](react-native/examples/session-join-pattern.md) - Tokenized session join flow
• [flutter/SKILL.md](flutter/SKILL.md) - Flutter Video SDK (mobile wrapper, event-driven architecture)
• [flutter/SKILL.md](flutter/SKILL.md) - Flutter documentation navigation
• [flutter/examples/session-join-pattern.md](flutter/examples/session-join-pattern.md) - Tokenized session join flow
• [android/SKILL.md](android/SKILL.md) - Android Video SDK (native mobile custom UI, tokenized sessions)
• [ios/SKILL.md](ios/SKILL.md) - iOS Video SDK (native mobile custom UI, delegate-driven lifecycle)
• [macos/SKILL.md](macos/SKILL.md) - macOS Video SDK (desktop native apps, custom session windows)
• [unity/SKILL.md](unity/SKILL.md) - Unity Video SDK wrapper (game-engine integration, scene-driven UX)
• [linux/SKILL.md](linux/SKILL.md) - Linux Video SDK overview (C++ headless bots)
• [linux/linux.md](linux/linux.md) - Linux C++ SDK (headless bots, raw media capture/injection)
• [linux/references/linux-reference.md](linux/references/linux-reference.md) - Linux API Reference
• [windows/SKILL.md](windows/SKILL.md) - Windows C++ SDK (desktop applications, raw media capture/injection)
• [windows/references/windows-reference.md](windows/references/windows-reference.md) - Windows API Reference
• [references/troubleshooting.md](references/troubleshooting.md) - Common issues and solutions
• [references/forum-top-questions.md](references/forum-top-questions.md) - Common forum question patterns (what to cover)

Sample Repositories

Official (by Zoom)

Full list: See general/references/community-repos.md

Resources

• Official docs: https://developers.zoom.us/docs/video-sdk/
• Developer forum: https://devforum.zoom.us/

Environment Variables

• See references/environment-variables.md for standardized .env keys and where to find each value.

Linux Operations

• linux/RUNBOOK.md - Linux platform preflight and debugging checklist.