n8n Auto Expense Tracker from LINE Messages with GPT-4 and Google Sheets

This n8n workflow automates the process of extracting expense details from LINE messages using GPT-4 and recording them into a Google Sheet. It's designed to streamline personal or business expense tracking by intelligently parsing natural language messages.

What it does

This workflow performs the following key steps:

1. Listens for LINE Messages: It acts as a webhook listener, waiting for incoming messages from LINE.
2. Extracts Expense Data with AI: It uses an OpenAI Chat Model (GPT-4) in conjunction with a Structured Output Parser to extract specific expense details (e.g., item, amount, category) from the received LINE message text.
3. Formats Data: It prepares the extracted data into a structured format suitable for Google Sheets.
4. Records to Google Sheets: It appends the parsed expense information as a new row in a designated Google Sheet.
5. Handles Errors/Responses: It can be extended to provide feedback or handle cases where expense data cannot be extracted.

Prerequisites/Requirements

To use this workflow, you will need:

• n8n Instance: A running n8n instance.
• LINE Account: A LINE Developers account with a Messaging API channel configured to send webhook events to your n8n instance.
• OpenAI API Key: An API key for OpenAI (specifically for GPT-4 or a compatible chat model).
• Google Account: A Google account with access to Google Sheets. You'll need to create a new spreadsheet or use an existing one for your expense data.
• n8n Credentials: Configured credentials in n8n for:
  • LINE (for the Webhook trigger)
  • OpenAI (for the OpenAI Chat Model node)
  • Google Sheets (for the Google Sheets node)

Setup/Usage

1. Import the Workflow:
   • Download the workflow JSON.
   • In your n8n instance, go to "Workflows" and click "New".
   • Click the "Import from JSON" button and paste the workflow JSON.
2. Configure Credentials:
   • Locate the "Webhook" node and ensure it's configured to receive messages from your LINE Messaging API channel. You'll need to copy the webhook URL from this node and paste it into your LINE Developers console.
   • Locate the "OpenAI Chat Model" node and configure your OpenAI API key credential.
   • Locate the "Google Sheets" node and configure your Google Sheets credential. Specify the Spreadsheet ID and Sheet Name where you want to record expenses.
3. Activate the Workflow:
   • Once all credentials and configurations are set, activate the workflow by toggling the "Active" switch in the top right corner of the n8n editor.
4. Send LINE Messages:
   • Send a message to your LINE bot/channel with your expense details, for example: "I spent $25.50 on groceries today." or "Coffee for $4.20, category food."
   • The workflow will automatically process the message, extract the expense, and add it to your Google Sheet.

This workflow provides a powerful foundation for automated expense tracking directly from your LINE conversations.