WhatsApp Business API Automation in n8n: Start With the Window

说明与用途

使用 n8n 自动化 WhatsApp 回复，遵守 24 小时服务窗口，验证 Meta 签名，去重消息，并对 AI 草稿进行人工审核。

问题

Small businesses receive hundreds of WhatsApp messages and answer them manually; they need automated replies that respect WhatsApp’s rules and cost structure.

结果

An n8n workflow that respects WhatsApp’s 24‑hour window, avoids duplicate replies, and uses human review for AI‑drafted messages, reducing manual effort while staying compliant.

工作流

• Receive message via webhook
• Verify Meta signature using app secret
• Deduplicate by storing message_id in Postgres
• Determine message type (FAQ or human handoff)
• If FAQ, draft reply from fixed source
• Send draft to human for approval via WhatsApp
• If approved, send final message to customer

证据

The single most useful fact about the platform is the customer service window. According to the WhatsApp Business Platform pricing page, when a user messages a business it opens a 24-hour window in which the business can reply with service messages at no charge, and the window resets with each new user message.

来源

First, verify that the request came from Meta. Incoming requests carry a signature header you can check against your app secret.

来源

Second, deduplicate. If your workflow is slow and the sender decides it hasn't heard back, you can see the same message twice. I store each message ID in a small Postgres table and skip anything already seen.

来源