WhatsApp Cloud API with n8n: a missed-call follow-up that books the job

To reply on WhatsApp to every missed call, you need three pieces: your phone system tells n8n a call was missed, n8n sends an approved WhatsApp template through Meta's Cloud API, and replies come back to n8n so it can ask a couple of questions, send a booking link and hand over to a person. WhatsApp itself never sees the phone call, so the trigger has to come from your phone provider.

What you need before you start

• A Meta Business account and a WhatsApp Business number on the Cloud API, in your own name.
• A phone system that can send a webhook on a missed call, such as Twilio or most cloud PBX tools. A plain mobile number can't.
• n8n, self-hosted or Cloud. It has a WhatsApp Business Cloud node for sending and a WhatsApp trigger for replies.
• At least one message template approved by Meta, because you're writing first.

The Meta rules that shape the flow

• The 24-hour windowOnce a customer messages you, you can reply freely for 24 hours. Outside that window, every message you start must use an approved template.
• Opt-inWrite first only to people who gave you their number and expect to hear from you, and make it easy to stop. Messages people report as spam lower your number's quality rating and can limit how many you can send.
• You pay for templatesMeta charges for template messages by category and country, so the plan should estimate the monthly cost before you build.

The flow, step by step

1. 01Missed call webhookYour phone system calls an n8n webhook with the caller's number and the time.
2. 02Check before you sendSkip numbers that already have an open chat, opted out, or are in your contacts as staff or suppliers. Format the number in international form.
3. 03Send the templateSomething short: "Sorry we missed your call. What can we help with?" with two or three quick-reply buttons.
4. 04Read the replyThe WhatsApp trigger receives the answer. A Switch node routes each button; free text goes to a person.
5. 05Book or hand overSend a booking link for simple requests. For anything else, post a summary to Slack or your CRM and stop the automation for that chat.
6. 06Log every stepSave the number, the messages and the outcome, so you can see how many missed calls became bookings.

Keep a person in it

The automation should answer the easy part and get out of the way. Complaints, refunds and anything unclear go to a person, and once someone replies by hand the flow should stay quiet. An AI reply drafted from your own prices and FAQ can help, but I'd have a person approve it until the answers have proved reliable.

For many small businesses a pre-filled chat link is enough, and it costs nothing to run. The yoga site I built works that way, with click tracking on every button. I wrote about why in WhatsApp is the checkout.