Skip to main content

Automate invoice processing & stock management with AI, Gmail, Sheets & Slack

Workflow preview

Workflow preview
100%
Automate invoice processing & stock management with AI, Gmail, Sheets & Slack preview
Open on n8n.io

Important notice

This workflow is provided as-is. Please review and test before using in production.

1. Workflow Overview

What problem does this workflow solve? Order processing often involves manual invoice reading, stock checking, and back and forth communication between procurement and operations teams. This work...

Best for

  • Invoice Processing automation workflows
  • AI Summarization automation workflows
  • advanced n8n builders looking for reusable templates

Tools used

n8n-nodes-base.gmailtrigger, n8n-nodes-base.extractfromfile, @n8n/n8n-nodes-langchain.outputparserstructured, @n8n/n8n-nodes-langchain.lmchatopenai, n8n-nodes-base.gmail, @n8n/n8n-nodes-langchain.agent, n8n-nodes-base.googlesheets, n8n-nodes-base.if

Source and attribution

This workflow is cataloged by N8N Workflows and links back to its original n8n.io source page by InfyOm Technologies.

Original n8n.io source

1.1 Workflow description

Title
Automate invoice processing & stock management with AI, Gmail, Sheets & Slack
Workflow name
Automate invoice processing & stock management with AI, Gmail, Sheets & Slack

βœ… What problem does this workflow solve?

Order processing often involves manual invoice reading, stock checking, and back-and-forth communication between procurement and operations teams. This workflow automates the entire procurement decision flow β€” from reading incoming order emails to extracting structured data, checking stock, and creating either a purchase requisition or a work order automatically.


πŸ’‘ Main Use Cases

  • πŸ“₯ Auto-extract order and invoice details from incoming emails
  • πŸ“¦ Validate stock availability before processing orders
  • πŸ“ Auto-create Purchase Requisitions when stock is insufficient
  • πŸ›  Auto-create Work Orders when stock is available
  • πŸ“§ Notify procurement or operations via email & Slack
  • πŸ“Š Log every action in Google Sheets for tracking and audit

🧠 How It Works – Step-by-Step

1. πŸ“§ Gmail Trigger

The workflow begins when a new email arrives at a specific email address.
The invoice file is automatically downloaded for processing.


2. πŸ“‘ Extract Invoice Record

The attached invoice is processed using OCR or a document extraction tool.
Raw details such as:

  • Order ID
  • Item code
  • Quantity
  • Customer information

are extracted for further processing.


3. πŸ€– AI-Powered Data Structuring

OpenAI structures the extracted fields into a clean and consistent format:

  • order_id
  • item_code
  • quantity
  • customer_name

This ensures all data is normalised before stock validation.


4. πŸ“¦ Stock Check

The workflow checks inventory data stored in Google Sheets.
It compares:

  • Required quantity
  • Current stock

If stock is insufficient, it triggers the purchase requisition path.
If stock is available, it initiates the work order path.


5. πŸ”€ Conditional Flow

If stock is insufficient:
  • Creates a Purchase Requisition record in Google Sheets
  • Sends an email notification to the procurement team for approval
If stock is sufficient:
  • Creates a Work Order entry in Google Sheets
  • Sends a Slack summary message to the operations team

This ensures teams are notified instantly, and work continues without delays.


πŸ“Š Logging & Reporting

Every step β€” extracted data, PR created, WO created, notifications sent β€” is logged in Google Sheets.
This provides a full audit trail for procurement and operations teams.


πŸ‘€ Who can use this?

Ideal for:

  • Procurement teams
  • Operations departments
  • Manufacturing & warehouse units
  • Businesses processing high-volume emailed orders
  • Any team needing structured, automated order workflows

πŸš€ Benefits

  • ⏱ Faster order processing
  • 🧠 Fewer manual errors from invoice reading
  • πŸ“¦ Smarter procurement decisions based on real stock
  • πŸ” Automated communication loops
  • πŸ“Š Transparent audit logs for every order

1.2 Logical Blocks

This catalog entry is organized from the workflow JSON. The node-level section below shows the executable blocks available for review before importing the template.

2. Block-by-Block Analysis

Block 1 - Gmail Trigger

Type / Role
n8n-nodes-base.gmailTrigger - gmailTrigger
Config choices
Version 1.3

Block 2 - Extract from File

Type / Role
n8n-nodes-base.extractFromFile - extractFromFile
Config choices
Version 1

Block 3 - Structured Output Parser

Type / Role
@n8n/n8n-nodes-langchain.outputParserStructured - outputParserStructured
Config choices
Version 1.3

Block 4 - OpenAI Chat Model

Type / Role
@n8n/n8n-nodes-langchain.lmChatOpenAi - lmChatOpenAi
Config choices
Version 1.2

Block 5 - Send a message

Type / Role
n8n-nodes-base.gmail - gmail
Config choices
Version 2.1

Block 6 - Extract Invoice Record

Type / Role
@n8n/n8n-nodes-langchain.agent - agent
Config choices
Version 2.2

Block 7 - Sales Order Creation

Type / Role
n8n-nodes-base.googleSheets - googleSheets
Config choices
Version 4.7

Block 8 - Stock & Shortage Check

Type / Role
n8n-nodes-base.googleSheets - googleSheets
Config choices
Version 4.7

Block 9 - If Negative

Type / Role
n8n-nodes-base.if - if
Config choices
Version 2.2

Block 10 - Create Purchase Requisition

Type / Role
n8n-nodes-base.googleSheets - googleSheets
Config choices
Version 4.7

Block 11 - Create Work Order

Type / Role
n8n-nodes-base.googleSheets - googleSheets
Config choices
Version 4.7

Block 12 - Send Order Summary

Type / Role
n8n-nodes-base.slack - slack
Config choices
Version 2.3

Block 13 - Sticky Note

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 14 - Sticky Note1

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 15 - Sticky Note2

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

3. Summary Table

Workflow Automate invoice processing & stock management with AI, Gmail, Sheets & Slack
Complexity advanced
Nodes 15
Categories Invoice Processing, AI Summarization
Author InfyOm Technologies
Published 11 Dec 2025

4. Reproducing the Workflow from Scratch

  1. 1. Download the workflow JSON

    Use the JSON export at /data/workflows/11678/11678.json as the source template for this automation.

  2. 2. Import the template into n8n

    Open n8n, import the downloaded JSON, and review each node before activating the workflow.

  3. 3. Configure credentials and variables

    Replace placeholder credentials, API keys, webhook URLs, account IDs, and environment-specific values with your own settings.

  4. 4. Test with sample data

    Run the workflow manually or in a staging workspace, inspect node output, and confirm downstream systems receive the expected data.

  5. 5. Activate and monitor

    Enable the workflow only after testing, then monitor executions, errors, and rate limits during the first production runs.

5. General Notes & Resources

Review imported nodes carefully before activation. This catalog entry is intended to help you inspect the workflow structure, understand required services, and find related templates faster.

Node names, credentials, schedules, webhook paths, and external service limits may need adjustment for your workspace.

Frequently asked questions

What does Automate invoice processing & stock management with AI, Gmail, Sheets & Slack do?

What problem does this workflow solve? Order processing often involves manual invoice reading, stock checking, and back and forth communication between procurement and operations teams. This work...

What do I need before importing this workflow?

Review the workflow JSON, configure any required credentials in n8n, and test the automation in a safe workspace before using it in production.

Can I customize this workflow?

Yes. Use the block-by-block analysis and the downloadable JSON to inspect each node, then adjust credentials, prompts, schedules, filters, or destinations for your Invoice Processing, AI Summarization use case.