vercel__chat/packages/adapter-whatsapp

@chat-adapter/whatsapp

npm package: @chat-adapter/whatsapp

WhatsApp Business Cloud adapter for Chat SDK, using the WhatsApp Business Cloud API.

Documentation: chat-sdk.dev/adapters/official/whatsapp · Guides: vercel.com/kb/chat-sdk

Installation

pnpm add @chat-adapter/whatsapp

Scaffold with the CLI

To scaffold a new WhatsApp bot with this adapter preselected:

npx create-chat-sdk@latest my-bot --adapter whatsapp memory

Visit the adapters directory to see other available official and vendor-official adapters.

Usage

import { Chat } from "chat";
import { createWhatsAppAdapter } from "@chat-adapter/whatsapp";

const bot = new Chat({
  userName: "mybot",
  adapters: {
    whatsapp: createWhatsAppAdapter(),
  },
});

bot.onNewMention(async (thread, message) => {
  await thread.post("Hello from WhatsApp!");
});

When using createWhatsAppAdapter() without arguments, credentials are auto-detected from environment variables.

WhatsApp Business setup

1. Create a Meta app

1. Go to developers.facebook.com/apps
2. Click Create App, select Business type
3. Add the WhatsApp product to your app
4. Go to WhatsApp > API Setup and note your Phone Number ID and Access Token

2. Configure webhooks

1. Go to WhatsApp > Configuration in your Meta app
2. Set Callback URL to https://your-domain.com/api/webhooks/whatsapp
3. Set Verify Token to a secret string of your choice (this becomes WHATSAPP_VERIFY_TOKEN)
4. Subscribe to the messages webhook field

3. Get credentials

From your Meta app dashboard, copy:

• App Secret (under App Settings > Basic) as WHATSAPP_APP_SECRET
• Access Token (under WhatsApp > API Setup) as WHATSAPP_ACCESS_TOKEN
• Phone Number ID (under WhatsApp > API Setup) as WHATSAPP_PHONE_NUMBER_ID

For production, generate a permanent System User Token instead of the temporary access token.

Configuration

All options are auto-detected from environment variables when not provided. You can call createWhatsAppAdapter() with no arguments if the env vars are set.

Option	Required	Description
accessToken	No*	Meta access token. Auto-detected from WHATSAPP_ACCESS_TOKEN
appSecret	No*	App secret for webhook verification. Auto-detected from WHATSAPP_APP_SECRET
phoneNumberId	No*	Bot's phone number ID. Auto-detected from WHATSAPP_PHONE_NUMBER_ID
verifyToken	No*	Webhook verification secret. Auto-detected from WHATSAPP_VERIFY_TOKEN
apiVersion	No	Graph API version (defaults to v25.0)
userName	No	Bot username for self-message detection. Auto-detected from WHATSAPP_BOT_USERNAME (defaults to whatsapp-bot)
apiUrl	No	Override the Meta Graph API base URL. Auto-detected from WHATSAPP_API_URL
logger	No	Logger instance (defaults to ConsoleLogger("info"))

*Required at runtime — either via config or environment variable.

Environment variables

WHATSAPP_ACCESS_TOKEN=...          # Meta access token (permanent or system user token)
WHATSAPP_APP_SECRET=...            # App secret for X-Hub-Signature-256 verification
WHATSAPP_PHONE_NUMBER_ID=...       # Bot's phone number ID from Meta dashboard
WHATSAPP_VERIFY_TOKEN=...          # User-defined secret for webhook verification
WHATSAPP_BOT_USERNAME=...          # Optional, defaults to "whatsapp-bot"
WHATSAPP_API_URL=...               # Optional, override the Meta Graph API base URL

Webhook setup

WhatsApp uses two webhook mechanisms:

1. Verification handshake (GET) — Meta sends a hub.verify_token challenge that must match your WHATSAPP_VERIFY_TOKEN.
2. Event delivery (POST) — incoming messages, reactions, and interactive responses, verified via X-Hub-Signature-256.

// Next.js App Router example
import { bot } from "@/lib/bot";

export async function GET(request: Request) {
  return bot.webhooks.whatsapp(request);
}

export async function POST(request: Request) {
  return bot.webhooks.whatsapp(request);
}

Features

Messaging

Feature	Supported
Post message	Yes
Edit message	No (WhatsApp limitation)
Delete message	No (WhatsApp limitation)
Streaming	Buffered (accumulates then sends)
Mark as read	Yes
Auto-chunking	Yes (splits at 4096 chars)
Template messages	Yes (via sendTemplate)

Rich content

Feature	Supported
Interactive buttons	Yes (up to 3)
Link buttons	Partial (single link button becomes a native CTA URL message)
Button title limit	20 characters
List messages	Yes
Text fallback	Yes (for >3 buttons)

Conversations

Feature	Supported
Reactions	Yes (add and remove)
Typing indicator	Yes (requires a recent inbound message, marks it as read, and displays for up to 25 seconds)
DMs	Yes
Open DM	Yes

Typing indicators

WhatsApp supports typing indicators through thread.startTyping() or adapter.startTyping(threadId).

Use it when the bot is about to respond and may take a few seconds. The adapter uses the most recent inbound message ID from thread history, so startTyping() only works after the bot has received a message.

await thread.startTyping();

await thread.post({
  markdown: "Thanks, I am checking that now.",
});

WhatsApp-specific behavior:

• If there is no inbound message context, startTyping() no-ops.
• The typing indicator is dismissed when the bot sends its reply, or after the WhatsApp platform timeout.

Incoming message types

Type	Supported
Text	Yes
Images	Yes (with captions)
Documents	Yes (with captions)
Audio / Voice	Yes
Video	Yes (with captions)
Stickers	Yes
Locations	Yes (converted to map URL)
Interactive replies	Yes (button and list)
Reactions	Yes

Message history

Feature	Supported
Fetch messages	No (Cloud API limitation)
Fetch thread info	Yes

Interactive messages

Card elements are automatically converted to WhatsApp interactive messages:

• 3 or fewer buttons — rendered as WhatsApp reply buttons (max 20 chars per title)
• More than 3 buttons — falls back to formatted text
• Max body text — 1024 characters

When a card with reply buttons also contains link buttons, each link button is appended to the interactive message body as a Label: url line, since WhatsApp reply buttons cannot open URLs.

Link buttons (CTA URL)

A card whose only interactive element is a single link button is sent as a native CTA URL message with a tappable link button. The card is promoted only when all of these hold:

• The link button is the card's only action across every actions row, including rows nested in sections. Reply buttons, selects, radio selects, or a second populated actions row keep the text fallback.
• The URL starts with http:// or https:// and the label is non-empty. Other schemes (mailto:, tel:, relative paths) keep the text fallback because the Cloud API rejects them.
• The card has no header image and no image, table, chart, or inline link children. Text, fields, sections, and dividers are fine.
• The post has no files or attachments. When media accompanies the card, the adapter keeps the single captioned media send, and the caption includes a Label: url line for each link button.

The button label is truncated to 20 characters, the header (card title) to 60, and the body to 1024. Cards that do not match these rules fall back to formatted text, where link buttons render as Label: url.

Template messages

Outside the 24-hour customer service window, WhatsApp only accepts pre-approved template messages. Use sendTemplate to start business-initiated conversations:

const threadId = await adapter.openDM("15551234567");

await adapter.sendTemplate(threadId, {
  name: "appointment_reminder",
  language: "en",
  components: [
    {
      type: "body",
      parameters: [{ type: "text", text: "Tomorrow at 2pm" }],
    },
  ],
});

Templates must be created and approved in WhatsApp Manager before they can be sent. Quick reply button taps on a template arrive as button responses and are dispatched to your onAction handlers.

Thread ID format

whatsapp:{phoneNumberId}:{userWaId}

Example: whatsapp:1234567890:15551234567

Troubleshooting

Webhook verification failing

• Confirm WHATSAPP_VERIFY_TOKEN matches the value you entered in the Meta dashboard
• Ensure your endpoint returns the hub.challenge value for GET requests

Messages not arriving

• Check that you subscribed to the messages webhook field in Meta app settings
• Verify WHATSAPP_APP_SECRET is correct — signature verification silently rejects invalid payloads
• Ensure your phone number is registered and verified in the WhatsApp Business dashboard

"Invalid signature" errors

• Double-check WHATSAPP_APP_SECRET matches the value under App Settings > Basic
• The adapter uses HMAC-SHA256 to verify the X-Hub-Signature-256 header

Token expired

• Temporary tokens from the API Setup page expire after 24 hours
• For production, create a System User in Meta Business Suite and generate a permanent token

AI Coding Agents

If you use an AI coding agent such as OpenAI Codex, Claude Code, or Cursor, install the Chat SDK skill so it knows the SDK APIs, adapter patterns, and project conventions before writing code.

npx skills add vercel/chat

The skill references bundled documentation in node_modules/chat/docs, plus adapter guides and starter templates in the published package.

You can also install the Vercel Plugin for a broader agent toolkit — it includes the Chat SDK skill alongside specialist agents, agent slash commands, and more:

npx plugins add vercel/vercel-plugin

The plugin is optional; the skill alone is enough to build with Chat SDK.

For agent-readable documentation, see chat-sdk.dev/llms.txt (page index) or chat-sdk.dev/llms-full.txt (full text).

License

MIT