Zoom Apps SDK

Background reference for web apps that run inside the Zoom client. Prefer choose-zoom-approach first, then route here for Layers API, Collaborate Mode, in-client OAuth, and runtime constraints.

Zoom Apps SDK

Build web apps that run inside the Zoom client - meetings, webinars, main client, and Zoom Phone.

Official Documentation: https://developers.zoom.us/docs/zoom-apps/ SDK Reference: https://appssdk.zoom.us/ NPM Package: https://www.npmjs.com/package/@zoom/appssdk

Quick Links

New to Zoom Apps? Follow this path:

1. Architecture - Frontend/backend pattern, embedded browser, deep linking
2. Quick Start - Complete working Express + SDK app
3. Running Contexts - Where your app runs (inMeeting, inMainClient, etc.)
4. Zoom Apps vs Meeting SDK - Stop mixing app types
5. In-Client OAuth - Seamless authorization with PKCE
6. API Reference - 100+ SDK methods
7. Integrated Index - see the section below in this file
8. 5-Minute Runbook - Preflight checks before deep debugging

Reference:

• API Reference - All SDK methods by category
• Events Reference - All SDK event listeners
• Layers API - Immersive and camera mode rendering
• OAuth Reference - OAuth flows for Zoom Apps
• Zoom Mail - Mail plugin integration

Having issues?

• App won't load in Zoom → Check Domain Allowlist below
• SDK errors → Common Issues
• Local dev setup → Debugging Guide
• Version upgrade → Migration Guide
• Forum-derived FAQs → Forum Top Questions

Building immersive experiences?

• Layers Immersive Mode - Custom video layouts
• Camera Mode - Virtual camera overlays

Need help with OAuth? See the zoom-oauth skill for authentication flows.

SDK Overview

The Zoom Apps SDK (@zoom/appssdk) provides JavaScript APIs for web apps running in Zoom's embedded browser:

• Context APIs - Get meeting, user, and participant info
• Meeting Actions - Share app, invite participants, open URLs
• Authorization - In-Client OAuth with PKCE (no browser redirect)
• Layers API - Immersive video layouts and camera mode overlays
• Collaborate Mode - Shared app state across participants
• App Communication - Message passing between app instances (main client <-> meeting)
• Media Controls - Virtual backgrounds, camera listing, recording control
• UI Controls - Expand app, notifications, popout
• Events - React to meeting state, participants, sharing, and more

Prerequisites

• Zoom app configured as "Zoom App" type in Marketplace
• OAuth credentials (Client ID + Secret) with Zoom Apps scopes
• Web application (Node.js + Express recommended)
• Your domain whitelisted in Marketplace domain allowlist
• ngrok or HTTPS tunnel for local development
• Node.js 18+ (for the backend server)

Quick Start

Option A: NPM (Recommended for frameworks)

npm install @zoom/appssdk

import zoomSdk from '@zoom/appssdk';

async function init() {
  try {
    const configResponse = await zoomSdk.config({
      capabilities: [
        'shareApp',
        'getMeetingContext',
        'getUserContext',
        'openUrl'
      ],
      version: '0.16'
    });

    console.log('Running context:', configResponse.runningContext);
    // 'inMeeting' | 'inMainClient' | 'inWebinar' | 'inImmersive' | ...

    const context = await zoomSdk.getMeetingContext();
    console.log('Meeting ID:', context.meetingID);
  } catch (error) {
    console.error('Not running inside Zoom:', error.message);
    showDemoMode();
  }
}

Option B: CDN (Vanilla JS)

<script src="https://appssdk.zoom.us/sdk.js"></script>

<script>
// CRITICAL: Do NOT declare "let zoomSdk" - the SDK defines window.zoomSdk globally
// Using "let zoomSdk = ..." causes: SyntaxError: redeclaration of non-configurable global property
let sdk = window.zoomSdk;  // Use a different variable name

async function init() {
  try {
    const configResponse = await sdk.config({
      capabilities: ['shareApp', 'getMeetingContext', 'getUserContext'],
      version: '0.16'
    });

    console.log('Running context:', configResponse.runningContext);
  } catch (error) {
    console.error('Not running inside Zoom:', error.message);
    showDemoMode();
  }
}

function showDemoMode() {
  document.body.innerHTML = '<h1>Preview Mode</h1><p>Open this app inside Zoom to use.</p>';
}

document.addEventListener('DOMContentLoaded', () => {
  init();
  setTimeout(() => { if (!sdk) showDemoMode(); }, 3000);
});
</script>

Critical: Global Variable Conflict

The CDN script defines window.zoomSdk globally. Do NOT redeclare it:

// WRONG - causes SyntaxError in Zoom's embedded browser
let zoomSdk = null;
zoomSdk = window.zoomSdk;

// CORRECT - use different variable name
let sdk = window.zoomSdk;

// ALSO CORRECT - NPM import (no conflict)
import zoomSdk from '@zoom/appssdk';

This only applies to the CDN approach. The NPM import creates a module-scoped variable, no conflict.

Browser Preview / Demo Mode

The SDK only functions inside the Zoom client. When accessed in a regular browser:

• window.zoomSdk exists but sdk.config() throws an error
• Always implement try/catch with fallback UI
• Add timeout (3 seconds) in case SDK hangs

URL Whitelisting (Required)

Your app will NOT load in Zoom unless the domain is whitelisted.

1. Go to Zoom Marketplace
2. Open your app -> Feature tab
3. Under Zoom App, find Add Allow List
4. Add your domain (e.g., yourdomain.com for production, xxxxx.ngrok.io for dev)

Without this, the Zoom client shows a blank panel with no error message.

OAuth Scopes (Required)

Capabilities require matching OAuth scopes enabled in Marketplace:

To add scopes: Marketplace -> Your App -> Scopes tab -> Add required scopes.

Missing scopes = capability fails silently or throws error. Users must re-authorize if you add new scopes.

Running Contexts

Your app runs in different surfaces within Zoom. The configResponse.runningContext tells you where:

See Running Contexts for context-specific behavior and APIs.

SDK Initialization Pattern

Every Zoom App starts with config():

import zoomSdk from '@zoom/appssdk';

const configResponse = await zoomSdk.config({
  capabilities: [
    // List ALL APIs you will use
    'getMeetingContext',
    'getUserContext',
    'shareApp',
    'openUrl',
    'authorize',
    'onAuthorized'
  ],
  version: '0.16'
});

// configResponse contains:
// {
//   runningContext: 'inMeeting',
//   clientVersion: '5.x.x',
//   unsupportedApis: []  // APIs not supported in this client version
// }

Rules:

1. config() MUST be called before any other SDK method
2. Only capabilities listed in config() are available
3. Capabilities must match OAuth scopes in Marketplace
4. Check unsupportedApis for graceful degradation

In-Client OAuth (Summary)

Best UX for authorization - no browser redirect:

// 1. Get code challenge from your backend
const { codeChallenge, state } = await fetch('/api/auth/challenge').then(r => r.json());

// 2. Trigger in-client authorization
await zoomSdk.authorize({ codeChallenge, state });

// 3. Listen for authorization result
zoomSdk.addEventListener('onAuthorized', async (event) => {
  const { code, state } = event;
  // 4. Send code to backend for token exchange
  await fetch('/api/auth/token', {
    method: 'POST',
    body: JSON.stringify({ code, state })
  });
});

See In-Client OAuth Guide for complete implementation.

Layers API (Summary)

Build immersive video layouts and camera overlays:

// Start immersive mode - replaces gallery view
await zoomSdk.runRenderingContext({ view: 'immersive' });

// Position participant video feeds
await zoomSdk.drawParticipant({
  participantUUID: 'user-uuid',
  x: 0, y: 0, width: 640, height: 480, zIndex: 1
});

// Add overlay images
await zoomSdk.drawImage({
  imageData: canvas.toDataURL(),
  x: 0, y: 0, width: 1280, height: 720, zIndex: 0
});

// Exit immersive mode
await zoomSdk.closeRenderingContext();

See Layers Immersive and Camera Mode.

Environment Variables

Common APIs

Complete Documentation Library

Core Concepts

• Architecture - Frontend/backend pattern, embedded browser, deep linking, X-Zoom-App-Context
• Running Contexts - All contexts, context-specific APIs, multi-instance communication
• Security - OWASP headers, CSP, cookie security, PKCE, token storage

Complete Examples

• Quick Start - Hello World Express + SDK app
• In-Client OAuth - PKCE authorization flow
• Layers Immersive - Custom video layouts
• Camera Mode - Virtual camera overlays
• Collaborate Mode - Shared state across participants
• Guest Mode - Unauthenticated/authenticated/authorized states
• Breakout Rooms - Room detection and cross-room state
• App Communication - connect + postMessage between instances

Troubleshooting

• Common Issues - Quick diagnostics and error codes
• Debugging - Local dev, ngrok, browser preview
• Migration - SDK version upgrade notes

References

• API Reference - All 100+ SDK methods
• Events Reference - All SDK event listeners
• Layers API Reference - Drawing and rendering methods
• OAuth Reference - OAuth flows for Zoom Apps
• Zoom Mail - Mail plugin integration

Sample Repositories

Official (by Zoom)

Recommended for new projects: Use @zoom/appssdk version ^0.16.26.

Community

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

Learning Path

1. Start: zoomapps-sample-js - Simplest, most up-to-date
2. Advanced: zoomapps-advancedsample-react - Comprehensive (In-Client OAuth, Guest Mode, Collaborate)
3. Specialized: Pick based on feature (Layers, Serverless, Camera Mode)

Critical Gotchas (From Real Development)

1. Global Variable Conflict

The CDN script defines window.zoomSdk. Declaring let zoomSdk in your code causes SyntaxError: redeclaration of non-configurable global property. Use let sdk = window.zoomSdk or the NPM import.

2. Domain Allowlist

Your app URL must be in the Marketplace domain allowlist. Without it, Zoom shows a blank panel with no error. Also add appssdk.zoom.us and any CDN domains you use.

3. Capabilities Must Be Listed

Only APIs listed in config({ capabilities: [...] }) are available. Calling an unlisted API throws an error. This is also true for event listeners.

4. SDK Only Works Inside Zoom

zoomSdk.config() throws outside the Zoom client. Always wrap in try/catch with browser fallback:

try { await zoomSdk.config({...}); } catch { showBrowserPreview(); }

5. ngrok URL Changes

Free ngrok URLs change on restart. You must update 4 places in Marketplace: Home URL, Redirect URL, OAuth Allow List, Domain Allow List. Consider ngrok paid plan for stable subdomain.

6. In-Client OAuth vs Web OAuth

Use zoomSdk.authorize() (In-Client) for best UX - no browser redirect. Only fall back to web redirect for initial install from Marketplace.

7. Camera Mode CEF Race Condition

Camera mode uses CEF which takes time to initialize. drawImage/drawWebView may fail if called too early. Implement retry with exponential backoff.

8. Cookie Configuration

Zoom's embedded browser requires cookies with SameSite=None and Secure=true. Without this, sessions break silently.

9. State Validation

Always validate the OAuth state parameter to prevent CSRF attacks. Generate cryptographically random state, store it, and verify on callback.

Resources

• Official docs: https://developers.zoom.us/docs/zoom-apps/
• SDK reference: https://appssdk.zoom.us/
• NPM package: https://www.npmjs.com/package/@zoom/appssdk
• Developer forum: https://devforum.zoom.us/
• GitHub SDK source: https://github.com/zoom/appssdk

Need help? Start with Integrated Index section below for complete navigation.

Integrated Index

This section was migrated from SKILL.md.

Quick Start Path

If you're new to Zoom Apps, follow this order:

1. Run preflight checks first -> RUNBOOK.md

2. Read the architecture -> concepts/architecture.md

   • Frontend/backend pattern, embedded browser, deep linking
   • Understand how Zoom loads and communicates with your app

3. Build your first app -> examples/quick-start.md

   • Complete Express + SDK Hello World
   • ngrok setup for local development

4. Understand running contexts -> concepts/running-contexts.md

   • Where your app runs (inMeeting, inMainClient, inWebinar, etc.)
   • Context-specific APIs and limitations

5. Implement OAuth -> examples/in-client-oauth.md

   • In-Client OAuth with PKCE (best UX)
   • Token exchange and storage

6. Add features -> references/apis.md

   • 100+ SDK methods organized by category
   • Code examples for each

7. Troubleshoot -> troubleshooting/common-issues.md

   • Quick diagnostics for common problems

Documentation Structure

zoom-apps-sdk/
├── SKILL.md                           # Main skill overview
├── SKILL.md                           # This file - navigation guide
│
├── concepts/                          # Core architectural patterns
│   ├── architecture.md               # Frontend/backend, embedded browser, OAuth flow
│   ├── running-contexts.md           # Where your app runs + context-specific APIs
│   └── security.md                   # OWASP headers, CSP, data access layers
│
├── examples/                          # Complete working code
│   ├── quick-start.md                # Hello World - minimal Express + SDK app
│   ├── in-client-oauth.md            # In-Client OAuth with PKCE
│   ├── layers-immersive.md           # Layers API - immersive mode (custom layouts)
│   ├── layers-camera.md              # Layers API - camera mode (virtual camera)
│   ├── collaborate-mode.md           # Collaborate mode (shared state)
│   ├── guest-mode.md                 # Guest mode (unauthenticated -> authorized)
│   ├── breakout-rooms.md             # Breakout room integration
│   └── app-communication.md          # connect + postMessage between instances
│
├── troubleshooting/                   # Problem solving guides
│   ├── common-issues.md              # Quick diagnostics, error codes
│   ├── debugging.md                  # Local dev setup, ngrok, browser preview
│   └── migration.md                  # SDK version migration notes
│
└── references/                        # Reference documentation
    ├── apis.md                        # Complete API reference (100+ methods)
    ├── events.md                      # All SDK events
    ├── layers-api.md                  # Layers API detailed reference
    ├── oauth.md                       # OAuth flows for Zoom Apps
    └── zmail-sdk.md                   # Zoom Mail integration

By Use Case

I want to build a basic Zoom App

1. Architecture - Understand the pattern
2. Quick Start - Build Hello World
3. In-Client OAuth - Add authorization
4. Security - Required headers

I want immersive video layouts (Layers API)

1. Layers Immersive - Custom video positions
2. Layers API Reference - All drawing methods
3. App Communication - Sync layout across participants

I want a virtual camera overlay

1. Camera Mode - Camera mode rendering
2. Layers API Reference - Drawing methods

I want real-time collaboration

1. Collaborate Mode - Shared state APIs
2. App Communication - Instance messaging

I want guest/anonymous access

1. Guest Mode - Three authorization states
2. In-Client OAuth - promptAuthorize flow

I want breakout room support

1. Breakout Rooms - Room detection and state sync

I want to sync between main client and meeting

1. App Communication - connect + postMessage
2. Running Contexts - Multi-instance behavior

I want serverless deployment

1. Quick Start - Understand the base pattern first
2. Sample: zoomapps-serverless-vuejs - Firebase pattern

I want to add Zoom Mail integration

1. Zoom Mail Reference - REST API + mail plugins

I'm getting errors

1. Common Issues - Quick diagnostic table
2. Debugging - Local dev setup, DevTools
3. Migration - Version compatibility

Most Critical Documents

1. Architecture (FOUNDATION)

concepts/architecture.md

Understand how Zoom Apps work: Frontend in embedded browser, backend for OAuth/API, SDK as the bridge. Without this, nothing else makes sense.

2. Quick Start (FIRST APP)

examples/quick-start.md

Complete working code. Get something running before diving into advanced features.

3. Common Issues (MOST COMMON PROBLEMS)

troubleshooting/common-issues.md

90% of Zoom Apps issues are: domain allowlist, global variable conflict, or missing capabilities.

Key Learnings

Critical Discoveries:

1. Global Variable Conflict is the #1 Gotcha

   • CDN script defines window.zoomSdk globally
   • let zoomSdk = ... causes SyntaxError in Zoom's browser
   • Use let sdk = window.zoomSdk or NPM import

2. Domain Allowlist is Non-Negotiable

   • App shows blank panel with zero error if domain not whitelisted
   • Must include your domain AND appssdk.zoom.us AND any CDN domains
   • ngrok URLs change on restart - must update Marketplace each time

3. config() Gates Everything

   • Must be called first, must list all capabilities
   • Unlisted capabilities throw errors
   • Check unsupportedApis for client version compatibility

4. In-Client OAuth > Web OAuth for UX

   • authorize() keeps user in Zoom (no browser redirect)
   • Web redirect only needed for initial Marketplace install
   • Always implement PKCE (code_verifier + code_challenge)

5. Two App Instances Can Run Simultaneously

   • Main client instance + meeting instance
   • Use connect() + postMessage() to sync between them
   • Pre-meeting setup in main client, use in meeting

6. Camera Mode Has CEF Quirks

   • CEF initialization takes time
   • Draw calls may fail if too early
   • Use retry with exponential backoff

7. Cookie Settings Matter

   • SameSite=None + Secure=true required
   • Without this, sessions silently fail in embedded browser

Quick Reference

"App shows blank panel"

-> Domain Allowlist - add domain to Marketplace

"SyntaxError: redeclaration"

-> Global Variable - use let sdk = window.zoomSdk

"config() throws error"

-> Browser Preview - SDK only works inside Zoom

"API call fails silently"

-> OAuth Scopes - add required scopes in Marketplace

"How do I implement [feature]?"

-> API Reference - find the method, check capabilities needed

"How do I test locally?"

-> Debugging Guide - ngrok + Marketplace config

Document Version

Based on @zoom/appssdk v0.16.x (latest: 0.16.26+)

Happy coding!

Start with Architecture to understand the pattern, then Quick Start to build your first app.