How do I build a WhatsApp customer service bot in n8n?

How it works

1. Connect webhook arrives
2. Signature and token
3. Seen before?
4. Contact state
5. Decide
6. AI · person · hours · media · opt-out
7. POST /v1/messages

And on the side: message.echo (you replied from the phone) → the bot goes quiet in that chat · a failed message.status → logged and alerted, no retry.

What it does, one by one

• Checks the message comes from Connect: the header token (n8n checks it before running anything) and the HMAC signature X-Connect-Signature-256 over timestamp.body, with a 5-minute tolerance. A bad signature gets a 401.
• Never replies twice. Connect retries when it doesn't get a 2xx (the same event, with the same id), and when Meta re-delivers a message Connect doesn't send it again as a new event. The workflow records the WhatsApp id and also sends an Idempotency-Key tied to it: even if something repeats, Connect doesn't send another reply.
• Replies with AI reading your business instructions (what you sell, hours, tone) from a single field, with per-contact memory. The model is a separate node: OpenAI is wired, and a Claude node is ready to swap in.
• Hands off to a person when the customer asks or when the AI doesn't know (it answers a marker the customer never sees): it tells them someone will take over, alerts you and goes quiet in that chat for the hours you choose.
• 🔑 If you reply from your phone, the bot goes quiet in that chat for as long as you choose. Coexistence makes this possible: Connect sends you message.echo with what you typed in the app. When the bot comes back, the AI knows what you said.
• Opening hours: outside them it sends one message and nothing else (it doesn't repeat on every message).
• Audio, image, video, sticker, location: an honest reply («I only read text, can you type it?»), not silence.
• Opt-out: if they write «baja» or «stop», it confirms once and never writes again; «alta» or «start» brings them back.
• Errors: if Connect rejects a send (wrong key, expired trial, disconnected number, quota) or Meta rejects it later (e.g. the 24-hour window), it's written to a table and you get an alert. It never retries, and a failed alert doesn't trigger another alert: no loop is possible.
• 🔑 The history: if you chose to receive the Coexistence history when connecting, it keeps the last 30 messages of each contact (never the hundreds of thousands) and the AI reads them as «what you talked about before» when that customer writes again. A repeated batch duplicates nothing. When it ends (or if it couldn't be stored) you get an alert.

Download it

Download the workflow (JSON)

Get it running in 5 steps

1. Import it. In n8n: Workflows → ⋮ → Import from File and pick the JSON. Press ▶ on the Run once: create tables node (it creates the 4 tables it uses: duplicates, contacts, errors and history).
2. Credentials (the workflow ships no secrets): Connect webhook token — type Header Auth, Name X-Connect-Token, Value your wct_… token; Connect API key — Header Auth, Name Authorization, Value Bearer wc_live_… (in the panel: API → Create API key); OpenAI (or Anthropic); and SMTP if you want email alerts.
3. Config. Open the Config node and describe your business in businessInstructions, your hours in openingHours, your email in ownerEmail. To check signatures, paste your whsec_… in signingSecret.
4. Activate it (the toggle at the top) and copy the Production URL of the Connect webhook node. ⚠ The Test URL listens only once.
5. In Connect → Webhooks → Add endpoint: that URL, events message.received, message.echo and message.status (plus history.batch, history.completed and history.dropped if you chose to receive the history when connecting), and generate the static token. Press Test: it must give 200. Then send yourself a WhatsApp from another phone.

Isn't n8n's own WhatsApp node enough?

n8n ships its own WhatsApp node, which talks straight to Meta. Often it's enough, and it's free: if you already have a Meta app, your number is on the Cloud API and you don't use the WhatsApp Business app on the phone, use that.

What changes with Connect, plainly (what we say about n8n's node comes from its code, version 2.40.7):

If you need nothing from the right-hand column, stick with n8n's node. The workflow still works as an example: the ideas (record the WhatsApp id, answer 200 before the AI, never send free text outside the 24 hours, never retry blindly) apply to any provider.

Worth knowing first

• It needs n8n 2.3.0 or newer: it uses Data tables, and the operation that creates the tables arrived in that version. We ran it end to end on 2.3.0 and on 2.40.7. On n8n Cloud you're already on a recent version; self-hosted, check the version at the bottom left. That's where it keeps duplicates, each contact's state and the errors; you'll see them under Data tables.
• The AI memory lives inside n8n: it's lost when n8n restarts and doesn't work in queue mode. For something durable, swap the memory node for the Postgres or Redis one with the same key.
• The signing secret stays inside the workflow (Config node): n8n doesn't let a node read a credential. Remove it before exporting or sharing the workflow. The header token and the API key do live in credentials.
• n8n's Code node can't use crypto on a self-hosted install (it's disallowed by default): that's why the signature is computed with the Crypto node.
• The alert to your WhatsApp goes as a template, never as free text: outside the 24-hour window Meta rejects it. Without an approved template, use email.
• The app's automatic messages (greeting, away) also leave from the phone. We couldn't measure it: if you have them on, they may count as your reply and silence the bot.
• Service is the free-form text you reply within 24 hours of your customer's last message. Since 1 October 2026 Meta charges it per delivered message (in its rate card, the same figure as each country's utility rate), and also utility sent while the window is open. The first 1,000 service messages per number per month are free; after that Meta charges for each reply and needs your card added in Meta. Meta charges this, not WAIA Connect: your trial is still free. The 24-hour window still exists and defines whether you can send free-form text. Connect adds nothing to each bot reply.

Does your bot live in a Google Sheet?

If you don't use n8n and built your bot on a spreadsheet, there's the Google Sheets guide. The exact shape of every event is in Receive the webhook.

Sources (checked on 2026-09-29)

• n8n: the WhatsApp trigger
• n8n: the WhatsApp node
• n8n: modules allowed in the Code node (NODE_FUNCTION_ALLOW_BUILTIN)
• n8n: Data tables
• n8n: Simple Memory and queue mode