Extract Data from Thai Government Letters with Mistral OCR and Store in Google Sheets

Description

LINE OCR Workflow to Extract and Save Thai Government Letters to Google Sheets

This template automates the extraction of structured data from Thai government letters received via LINE or uploaded to Google Drive. It uses Mistral AI for OCR and OpenAI for information extraction, saving results to a Google Sheet.

Who’s it for?

Thai government agencies or teams receiving official documents via LINE or Google Drive
Automation developers working with document intake and OCR
Anyone needing to extract fields from Thai scanned letters and store structured info

What it does

This n8n workflow:
Receives documents from two sources:
LINE webhook (via Messaging API)
Google Drive (new file trigger)
Checks file type (PDF or image)
Runs OCR with Mistral AI (Document or Image model)
Uses OpenAI to extract key metadata such as:
book_id
subject
recipient (to)
signatory
date, contact info, etc.
Stores structured data in Google Sheets
Replies to LINE user with extracted info or moves files into archive folders (Drive)

How to Set It Up

Create a Google Sheet with a tab named data and the following columns Example Google Sheet:
book_id, date, subject, to, attach, detail, signed_by, signed_by_position, contact_phone, contact_email, download_url
Set up required credentials:
googleDriveOAuth2Api
googleSheetsOAuth2Api
httpHeaderAuth for LINE Messaging API
openAiApi
mistralCloudApi
Define environment variables:
LINE_CHANNEL_ACCESS_TOKEN
GDRIVE_INVOICE_FOLDER_ID
GSHEET_ID
MISTRAL_API_KEY
Deploy webhook to receive files from LINE Messaging API (Path: /line-invoice)
Monitor Drive uploads using Google Drive Trigger

How to Customize the Workflow

Adjust the information extraction schema in the OpenAI Information Extractor node to match your document layout
Add logic for different document types if you have more than one format
Modify the LINE Reply message format or use Flex Message
Update the Move File node if you want to archive to a different folder

Requirements

n8n self-hosted or cloud instance
Google account with access to Drive and Sheets
LINE Developer Account
OpenAI API key
Mistral Cloud API key

Notes

Community nodes used: @n8n/n8n-nodes-base.mistralAi
This workflow supports both document images and PDF files
File handling is done dynamically via MIME type