Billy Christi This workflow corresponds to n8n.io template #4452 — we link there as the canonical source.
This workflow follows the Agent → Form Trigger recipe pattern — see all workflows that pair these two integrations.
The workflow JSON
Copy or download the full n8n JSON below. Paste it into a new n8n workflow, add your credentials, activate. Full import guide →
{
"nodes": [
{
"id": "59b4e37b-f52f-415a-bb6f-7a249984ec3a",
"name": "OpenAI Chat Model",
"type": "@n8n/n8n-nodes-langchain.lmChatOpenAi",
"position": [
3280,
840
],
"parameters": {
"model": {
"__rl": true,
"mode": "list",
"value": "gpt-4o-mini"
},
"options": {}
},
"credentials": {
"openAiApi": {
"name": "<your credential>"
}
},
"typeVersion": 1.2
},
{
"id": "d9d53795-da16-4921-9c50-a4ce036b564f",
"name": "Structured Output Parser",
"type": "@n8n/n8n-nodes-langchain.outputParserStructured",
"position": [
3500,
840
],
"parameters": {
"jsonSchemaExample": "{\n \"invoice_number\": \"\",\n \"invoice_date\": \"\",\n \"due_date\": \"\",\n \"vendor_name\": \"\",\n \"total_amount\": \"\",\n \"currency\": \"\",\n \"items\": [\n {\n \"description\": \"\",\n \"amount\": \"\"\n }\n ],\n \"tax\": \"\",\n \"category\": \"\"\n}"
},
"typeVersion": 1.2
},
{
"id": "69406dc2-fb14-40bd-a24b-5fa28aaa338c",
"name": "Invoice Folder Monitor",
"type": "n8n-nodes-base.googleDriveTrigger",
"position": [
2620,
420
],
"parameters": {
"event": "fileCreated",
"options": {},
"pollTimes": {
"item": [
{
"mode": "everyMinute"
}
]
},
"triggerOn": "specificFolder",
"folderToWatch": {
"__rl": true,
"mode": "id",
"value": "1KJ4fvXcKVMGJunsKvPYf8PkX5K9SVwFk"
}
},
"credentials": {
"googleDriveOAuth2Api": {
"name": "<your credential>"
}
},
"typeVersion": 1
},
{
"id": "ab3bbd35-7d81-482e-a9f6-242c7b98cd49",
"name": "Download Invoice PDF",
"type": "n8n-nodes-base.googleDrive",
"position": [
2820,
420
],
"parameters": {
"fileId": {
"__rl": true,
"mode": "id",
"value": "={{ $json.id }}"
},
"options": {},
"operation": "download"
},
"credentials": {
"googleDriveOAuth2Api": {
"name": "<your credential>"
}
},
"typeVersion": 3
},
{
"id": "fc5a0c82-a1e9-468d-a2a5-0f8e7291f1d9",
"name": "Invoice Parser AI Agent",
"type": "@n8n/n8n-nodes-langchain.agent",
"position": [
3300,
640
],
"parameters": {
"text": "=You are an intelligent invoice parser. I will give you raw text extracted from a PDF invoice. \n\n========================\nSTART OF RAW INVOICE TEXT\n\n{{ $json.text }}\n\nEND OF RAW INVOICE TEXT\n========================\n\nYour job is to:\n\n1. Extract key information from the invoice such as:\n - invoice_number\n - invoice_date\n - due_date (if available)\n - vendor_name\n - total_amount\n - currency (e.g., USD, IDR, etc.)\n - items (as a list of item descriptions and their amounts)\n - tax (if available)\n\n2. Detect the invoice **category**, such as:\n - Utilities\n - Office Supplies\n - Travel\n - Software\n - Food & Beverage\n - Others (if unknown)\n\n3. Return the result in this exact JSON format:\n\n```json\n{\n \"invoice_number\": \"\",\n \"invoice_date\": \"\",\n \"due_date\": \"\",\n \"vendor_name\": \"\",\n \"total_amount\": \"\",\n \"currency\": \"\",\n \"items\": [\n {\n \"description\": \"\",\n \"amount\": \"\"\n }\n ],\n \"tax\": \"\",\n \"category\": \"\"\n}\n",
"options": {},
"promptType": "define",
"hasOutputParser": true
},
"typeVersion": 1.9
},
{
"id": "bb0a4401-9feb-4240-a62f-ad90c6c642a1",
"name": "Insert Invoice Data",
"type": "n8n-nodes-base.googleSheets",
"position": [
4180,
640
],
"parameters": {
"columns": {
"value": {
"Tax": "={{ $('Invoice Parser AI Agent').item.json.output.tax }}",
"Items": "={{ $('Invoice Parser AI Agent').item.json.output.items }}",
"Approved": "={{ $json.data['Approve Invoice?'] }}",
"Category": "={{ $('Invoice Parser AI Agent').item.json.output.category }}",
"Currency": "={{ $('Invoice Parser AI Agent').item.json.output.currency }}",
"Due Date": "={{ $('Invoice Parser AI Agent').item.json.output.due_date }}",
"Reviewed By": "={{ $json.data['Reviewed By'] }}",
"Vendor Name": "={{ $('Invoice Parser AI Agent').item.json.output.vendor_name }}",
"Invoice Date": "={{ $('Invoice Parser AI Agent').item.json.output.invoice_date }}",
"Total Amount": "={{ $('Invoice Parser AI Agent').item.json.output.total_amount }}",
"Approval Notes": "={{ $json.data['Approval Notes'] }}",
"Invoice Number": "={{ $('Invoice Parser AI Agent').item.json.output.invoice_number }}"
},
"schema": [
{
"id": "Invoice Number",
"type": "string",
"display": true,
"required": false,
"displayName": "Invoice Number",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Invoice Date",
"type": "string",
"display": true,
"required": false,
"displayName": "Invoice Date",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Due Date",
"type": "string",
"display": true,
"required": false,
"displayName": "Due Date",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Vendor Name",
"type": "string",
"display": true,
"required": false,
"displayName": "Vendor Name",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Total Amount",
"type": "string",
"display": true,
"required": false,
"displayName": "Total Amount",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Currency",
"type": "string",
"display": true,
"required": false,
"displayName": "Currency",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Items",
"type": "string",
"display": true,
"required": false,
"displayName": "Items",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Tax",
"type": "string",
"display": true,
"required": false,
"displayName": "Tax",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Category",
"type": "string",
"display": true,
"required": false,
"displayName": "Category",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Approved",
"type": "string",
"display": true,
"required": false,
"displayName": "Approved",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Approval Notes",
"type": "string",
"display": true,
"required": false,
"displayName": "Approval Notes",
"defaultMatch": false,
"canBeUsedToMatch": true
},
{
"id": "Reviewed By",
"type": "string",
"display": true,
"required": false,
"displayName": "Reviewed By",
"defaultMatch": false,
"canBeUsedToMatch": true
}
],
"mappingMode": "defineBelow",
"matchingColumns": [],
"attemptToConvertTypes": false,
"convertFieldsToString": false
},
"options": {},
"operation": "append",
"sheetName": {
"__rl": true,
"mode": "list",
"value": "gid=0",
"cachedResultUrl": "https://docs.google.com/spreadsheets/d/1ueJfN5dFTXY3_AdvnYUL5_RjV9YwSFvbxwA_ivtqnJk/edit#gid=0",
"cachedResultName": "Invoices"
},
"documentId": {
"__rl": true,
"mode": "list",
"value": "1ueJfN5dFTXY3_AdvnYUL5_RjV9YwSFvbxwA_ivtqnJk",
"cachedResultUrl": "https://docs.google.com/spreadsheets/d/1ueJfN5dFTXY3_AdvnYUL5_RjV9YwSFvbxwA_ivtqnJk/edit?usp=drivesdk",
"cachedResultName": "Copy of PDF Invoice Parser - n8n template"
}
},
"credentials": {
"googleSheetsOAuth2Api": {
"name": "<your credential>"
}
},
"typeVersion": 4.5
},
{
"id": "d1980b52-aa0a-479b-892f-9e81abfb35f6",
"name": "Sticky Note2",
"type": "n8n-nodes-base.stickyNote",
"position": [
2260,
420
],
"parameters": {
"color": 4,
"width": 280,
"height": 600,
"content": "## SETUP REQUIRED\n**Author:** [Billy Christi](https://n8n.io/creators/billy/)\n\n**Copy the Google Sheet template here**: \n\ud83d\udc49 [PDF Invoice Parser with Approval Workflow \u2013 Google Sheet Template](https://docs.google.com/spreadsheets/d/1ueJfN5dFTXY3_AdvnYUL5_RjV9YwSFvbxwA_ivtqnJk/edit?gid=0#gid=0)\n\nGoogle Sheets Structure:\nSheet: \"Invoices\"\n\u2022 Column A: Invoice Number \n\u2022 Column B: Invoice Date \n\u2022 Column C: Due Date \n\u2022 Column D: Vendor Name \n\u2022 Column E: Total Amount \n\u2022 Column F: Currency \n\u2022 Column G: Items \n\u2022 Column H: Tax \n\u2022 Column I: Category \n\u2022 Column J: Approved\n\u2022 Column K: Approval Notes\n\u2022 Column L: Reviewed By\n\nRequired Credentials:\n\u2022 Google Drive Credential \n\u2022 Gmail Credential \n\u2022 Google Sheets Credential \n\u2022 OpenAI API Key (GPT-4)\n"
},
"typeVersion": 1
},
{
"id": "858e3989-352d-4d73-a299-394b73780d59",
"name": "Sticky Note3",
"type": "n8n-nodes-base.stickyNote",
"position": [
2600,
1060
],
"parameters": {
"color": 5,
"width": 700,
"height": 560,
"content": "## \ud83e\uddfe Automated PDF Invoice Processing & Approval Flow using OpenAI and Google Sheets\n\nWhat This Template Does:\n\n- Monitors **Google Drive**, **Gmail**, and a **web form** for incoming PDF invoices \n- Automatically downloads and extracts raw text from PDF attachments \n- Uses **GPT-4o-mini** to intelligently parse invoice data (invoice number, vendor, date, amount, tax, items, etc.) \n- Categorizes invoices into types such as *Utilities, Travel, Office Supplies, Food & Beverage, Others* \n- Sends a dynamic **approval request email** with an embedded decision form (Yes/No, reviewer name, notes) \n- Stores both approved and rejected invoice data into **Google Sheets** for recordkeeping \n- Sends rejection notifications to the finance team for follow-up \n- Provides a complete, automated approval pipeline with human oversight \n- Includes a structured JSON schema for consistent and error-free AI output \n- Polls input sources every minute to ensure timely and responsive processing \n- Ideal for businesses seeking to **automate their invoice approval and bookkeeping workflows** with AI\n\n"
},
"typeVersion": 1
},
{
"id": "9fa12368-2a78-4a94-9eec-4fcbfe2f0254",
"name": "Sticky Note4",
"type": "n8n-nodes-base.stickyNote",
"position": [
3340,
1060
],
"parameters": {
"color": 5,
"width": 620,
"height": 620,
"content": "## \ud83d\udccb WORKFLOW PROCESS OVERVIEW\n\n1. **Invoice Collection** \nInvoices are captured through three triggers: new PDFs in a Google Drive folder, incoming Gmail messages with PDF attachments, or direct uploads via a web form.\n\n2. **File Handling** \nIf uploaded via Drive, the PDF is downloaded using its file ID; if via Gmail or form, the PDF is already available as binary data.\n\n3. **Text Extraction** \nThe system extracts raw text from the PDF using the appropriate method based on its source (Drive, Email, or Form).\n\n4. **AI Data Parsing** \nGPT-4 processes the extracted text into structured JSON, identifying invoice details like vendor, date, amount, and categorizing the invoice.\n\n5. **Approval Request** \nAn email is sent to the reviewer with an approval form asking for a Yes/No decision along with optional notes.\n\n6. **Decision Routing** \nIf approved, the data moves forward for storage; if rejected, a notification is sent to the finance team.\n\n7. **Save Invoice Data** \nAll extracted and reviewed invoice data is saved into a Google Sheet, maintaining a full record of each invoice and its status.\n"
},
"typeVersion": 1
},
{
"id": "0aeca259-2a98-48c3-a892-94bf7eac802a",
"name": "Send Invoice for Approval",
"type": "n8n-nodes-base.gmail",
"position": [
3640,
640
],
"parameters": {
"sendTo": "user@example.com",
"message": "=A new invoice has been submitted and requires your review and approval:",
"options": {},
"subject": "=[Action Required] Invoice Approval Request \u2013 {{ $json.output.vendor_name }}",
"operation": "sendAndWait",
"formFields": {
"values": [
{
"fieldType": "dropdown",
"fieldLabel": "Approve Invoice?",
"fieldOptions": {
"values": [
{
"option": "Yes"
},
{
"option": "No"
}
]
},
"requiredField": true
},
{
"fieldLabel": "Reviewed By",
"requiredField": true
},
{
"fieldType": "textarea",
"fieldLabel": "Approval Notes"
}
]
},
"responseType": "customForm"
},
"credentials": {
"gmailOAuth2": {
"name": "<your credential>"
}
},
"typeVersion": 2.1
},
{
"id": "2224840e-b38b-4375-9726-4355db099d6c",
"name": "Monitor Email Attachments",
"type": "n8n-nodes-base.gmailTrigger",
"position": [
2820,
640
],
"parameters": {
"simple": false,
"filters": {},
"options": {
"downloadAttachments": true,
"dataPropertyAttachmentsPrefixName": "attachment_"
},
"pollTimes": {
"item": [
{
"mode": "everyMinute"
}
]
}
},
"credentials": {
"gmailOAuth2": {
"name": "<your credential>"
}
},
"typeVersion": 1.2
},
{
"id": "f4ff8acd-d3a0-45c4-89eb-5d32c2311cf0",
"name": "Upload Invoice (PDF) Form",
"type": "n8n-nodes-base.formTrigger",
"position": [
2820,
840
],
"parameters": {
"options": {},
"formTitle": "Upload Invoice (PDF)",
"formFields": {
"values": [
{
"fieldType": "file",
"fieldLabel": "Upload",
"multipleFiles": false,
"requiredField": true,
"acceptFileTypes": ".pdf"
}
]
},
"formDescription": "Upload your invoice PDF using this form."
},
"typeVersion": 2.2
},
{
"id": "c2c7545e-344e-480d-8ff7-c14a275460cb",
"name": "Extract Text from Drive PDF",
"type": "n8n-nodes-base.extractFromFile",
"position": [
3020,
420
],
"parameters": {
"options": {},
"operation": "pdf"
},
"typeVersion": 1
},
{
"id": "51b5bedc-ac31-4e31-a854-89d63c8fe410",
"name": "Extract Text from Email PDF",
"type": "n8n-nodes-base.extractFromFile",
"position": [
3020,
640
],
"parameters": {
"options": {},
"operation": "pdf",
"binaryPropertyName": "attachment_0"
},
"typeVersion": 1
},
{
"id": "aca28461-3f7b-4530-aaec-a61bb402895b",
"name": "Extract Text from Form PDF",
"type": "n8n-nodes-base.extractFromFile",
"position": [
3020,
840
],
"parameters": {
"options": {},
"operation": "pdf",
"binaryPropertyName": "Upload"
},
"typeVersion": 1
},
{
"id": "189f7e81-1391-4baa-baa1-63419f92cccb",
"name": "Check Approval Decision",
"type": "n8n-nodes-base.if",
"position": [
3900,
640
],
"parameters": {
"options": {},
"conditions": {
"options": {
"version": 2,
"leftValue": "",
"caseSensitive": true,
"typeValidation": "strict"
},
"combinator": "and",
"conditions": [
{
"id": "451bfdfc-f645-4e3c-91cc-895558f45b11",
"operator": {
"type": "string",
"operation": "equals"
},
"leftValue": "={{ $json.data['Approve Invoice?'] }}",
"rightValue": "Yes"
}
]
}
},
"typeVersion": 2.2
},
{
"id": "24d89a38-91cc-429d-af6a-8616d67c1e03",
"name": "Send Rejection Alert",
"type": "n8n-nodes-base.gmail",
"position": [
4040,
900
],
"parameters": {
"sendTo": "user@example.com",
"message": "=Hi Finance Team,\n\nAn invoice from {{ $('Invoice Parser AI Agent').item.json.output.vendor_name }} has been disapproved during the approval process.\n\nReviewed By: {{ $('Send Invoice for Approval').item.json.data['Reviewed By'] }}\nApproval Notes: {{ $('Send Invoice for Approval').item.json.data['Approval Notes'] }}\n\nPlease review and follow up as needed.\n\nThank you,\nAutomated Invoice System\n\n",
"options": {
"appendAttribution": false
},
"subject": "=[Alert] Invoice Disapproved \u2013 {{ $('Invoice Parser AI Agent').item.json.output.vendor_name }}",
"emailType": "text"
},
"credentials": {
"gmailOAuth2": {
"name": "<your credential>"
}
},
"typeVersion": 2.1
},
{
"id": "5a2f9411-4233-4173-8541-53ba13de6268",
"name": "Sticky Note",
"type": "n8n-nodes-base.stickyNote",
"position": [
4400,
340
],
"parameters": {
"color": 4,
"width": 380,
"height": 760,
"content": "# \ud83d\udc4b Hi, I\u2019m Billy\n\nI help businesses build **n8n workflows** & **AI automation projects**. \nNeed help with n8n or AI Automation projects? \nContact me and let\u2019s build your automation together.\n\n\ud83d\udce9 **Email:** billychartanto@gmail.com \n\ud83e\udd1d **n8n Creator:** [n8n.io/creators/billy](https://n8n.io/creators/billy/)\n\ud83c\udf10 **My n8n Projects:** [billychristi.com/n8n](https://www.billychristi.com/n8n) \n\n\n\n---\n\ud83d\udca1 Feel free to get in touch if you\u2019d like help on your next automation project or if you have any feedback or thoughts to share.\n"
},
"typeVersion": 1
}
],
"connections": {
"OpenAI Chat Model": {
"ai_languageModel": [
[
{
"node": "Invoice Parser AI Agent",
"type": "ai_languageModel",
"index": 0
}
]
]
},
"Download Invoice PDF": {
"main": [
[
{
"node": "Extract Text from Drive PDF",
"type": "main",
"index": 0
}
]
]
},
"Send Rejection Alert": {
"main": [
[
{
"node": "Insert Invoice Data",
"type": "main",
"index": 0
}
]
]
},
"Invoice Folder Monitor": {
"main": [
[
{
"node": "Download Invoice PDF",
"type": "main",
"index": 0
}
]
]
},
"Check Approval Decision": {
"main": [
[
{
"node": "Insert Invoice Data",
"type": "main",
"index": 0
}
],
[
{
"node": "Send Rejection Alert",
"type": "main",
"index": 0
}
]
]
},
"Invoice Parser AI Agent": {
"main": [
[
{
"node": "Send Invoice for Approval",
"type": "main",
"index": 0
}
]
]
},
"Structured Output Parser": {
"ai_outputParser": [
[
{
"node": "Invoice Parser AI Agent",
"type": "ai_outputParser",
"index": 0
}
]
]
},
"Monitor Email Attachments": {
"main": [
[
{
"node": "Extract Text from Email PDF",
"type": "main",
"index": 0
}
]
]
},
"Send Invoice for Approval": {
"main": [
[
{
"node": "Check Approval Decision",
"type": "main",
"index": 0
}
]
]
},
"Upload Invoice (PDF) Form": {
"main": [
[
{
"node": "Extract Text from Form PDF",
"type": "main",
"index": 0
}
]
]
},
"Extract Text from Form PDF": {
"main": [
[
{
"node": "Invoice Parser AI Agent",
"type": "main",
"index": 0
}
]
]
},
"Extract Text from Drive PDF": {
"main": [
[
{
"node": "Invoice Parser AI Agent",
"type": "main",
"index": 0
}
]
]
},
"Extract Text from Email PDF": {
"main": [
[
{
"node": "Invoice Parser AI Agent",
"type": "main",
"index": 0
}
]
]
}
}
}
Credentials you'll need
Each integration node will prompt for credentials when you import. We strip credential IDs before publishing — you'll add your own.
gmailOAuth2googleDriveOAuth2ApigoogleSheetsOAuth2ApiopenAiApi
Pro
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About this workflow
This workflow is ideal for:
Source: https://n8n.io/workflows/4452/ — original creator credit. Request a take-down →
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