LINE Inbox to Google Sheets CRM + Daily Gmail Digest (n8n)

Turn LINE inbound messages into a Google Sheets CRM—with an automatic daily Gmail follow‑up digest

This n8n workflow captures every inbound LINE text message, logs it into a Google Sheets CRM, lets you respond through a secured webhook, and sends a daily Gmail digest of contacts who still need a reply.

What this workflow does

• Receives LINE webhook events and checks that the event is a `text` message.
• Normalizes the payload, fetches the sender profile from the LINE API, and combines everything into one contact/message record.
• Writes to Google Sheets: appends inbound messages to the “Messages” sheet.
• Upserts contacts in the “Contacts” sheet by LINE user ID:
  • Increments message count
  • Sets needs_reply=true
• Handles owner replies via a separate webhook:
  • Validates an owner_key
  • Sends the reply back to the user using LINE push message API
• Logs outbound replies to “Messages” and updates the related contact to set needs_reply=false and last_reply_at.
• Runs daily at 09:00: reads contacts from Google Sheets, filters to needs_reply=true, and sends a plain-text Gmail digest.

Use cases

• Manage customer support chats from LINE while keeping a lightweight CRM in Google Sheets.
• Ensure no one gets missed with an automatic daily follow-up email via Gmail.
• Route team responses: submit replies through the owner webhook and keep message history synchronized.

Technical details

• LINE Messaging API webhooks (inbound) and push messaging (outbound)
• Google Sheets CRM tabs: Contacts and Messages
• n8n nodes referenced: if, set, gmail, merge, webhook, aggregate

Ideal for n8n users, automation engineers, and SaaS operators who want an auditable LINE-to-CRM workflow with Gmail-based daily reminders.