Validate bills of lading, send Gmail replies, and post JSON with Google Gemini

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1. Workflow Overview

Quick overview This workflow triggers on a Gmail message from a specific sender, extracts bill of lading data from an email attachment using Google Gemini, validates the extracted values with Pytho...

Best for

Document Extraction automation workflows
AI Summarization automation workflows
advanced n8n builders looking for reusable templates

Tools used

n8n-nodes-base.stickynote, n8n-nodes-base.gmailtrigger, @n8n/n8n-nodes-langchain.googlegemini, @n8n/n8n-nodes-langchain.agent, n8n-nodes-base.httprequest, n8n-nodes-base.gmailtool, @n8n/n8n-nodes-langchain.lmchatgooglegemini, @n8n/n8n-nodes-langchain.outputparserstructured

Source and attribution

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

Original n8n.io source

1.1 Workflow description

Title: Validate bills of lading, send Gmail replies, and post JSON with Google Gemini
Workflow name: Validate bills of lading, send Gmail replies, and post JSON with Google Gemini

Quick overview

This workflow triggers on a Gmail message from a specific sender, extracts bill of lading data from an email attachment using Google Gemini, validates the extracted values with Python, posts the structured JSON to a webhook URL, and replies to the sender with an HTML acceptance email.

How it works

Triggers when a new Gmail email arrives from the configured sender and downloads the attached document.
Uses Google Gemini to analyze the attachment and rewrite the bill of lading content into a structured Markdown format.
Uses a second Google Gemini agent with a structured output schema to convert the Markdown into validated JSON fields for shipper, consignee, shipment details, and line items.
Runs a Python validation that compares customer order package/weight values against the carrier line items and appends a validation result to the JSON.
Sends the resulting JSON payload to an external HTTP webhook endpoint.
Uses Google Gemini to draft an HTML acceptance reply email based on the validated data and sends it back to the original sender via Gmail.

Setup

Connect your Gmail OAuth2 credentials and set the sender filter (and any other Gmail Trigger options) to match the emails you want to process.
Add Google Gemini (PaLM) API credentials and confirm the selected Gemini models are available in your account.
Ensure the incoming emails include a compatible bill of lading attachment and update the binary attachment property name if it differs from attachment_0.
Replace the HTTP Request URL with your own endpoint that should receive the structured JSON payload.
Review the structured JSON schema and the Python validation logic to match your required fields and matching rules before enabling the workflow.

Customization

Any LLM provider can do the task, change Gemini with any AI you can use

Additional info

This is an example of prompt chaining. It is an AI agent workflow that shows the benefit of chaining several LLMs together.

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 - Sticky Note

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

Block 2 - Sticky Note1

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

Block 3 - Sticky Note2

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

Block 4 - Sticky Note3

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

Block 5 - When Email Received

Type / Role: n8n-nodes-base.gmailTrigger - gmailTrigger
Config choices: Version 1.4

Block 6 - Analyze Document with Gemini

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

Block 7 - AI Document Analyzer Agent

Type / Role: @n8n/n8n-nodes-langchain.agent - agent
Config choices: Version 3.1

Block 8 - Post to Webhook API

Type / Role: n8n-nodes-base.httpRequest - httpRequest
Config choices: Version 4.4

Block 9 - AI Validation Agent

Type / Role: @n8n/n8n-nodes-langchain.agent - agent
Config choices: Version 3.1

Block 10 - Send Gmail Message

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

Block 11 - Gemini Main Analysis 1

Type / Role: @n8n/n8n-nodes-langchain.lmChatGoogleGemini - lmChatGoogleGemini
Config choices: Version 1.1

Block 12 - Gemini Fallback Analysis 1

Type / Role: @n8n/n8n-nodes-langchain.lmChatGoogleGemini - lmChatGoogleGemini
Config choices: Version 1.1

Block 13 - Gemini Main Analysis 2

Type / Role: @n8n/n8n-nodes-langchain.lmChatGoogleGemini - lmChatGoogleGemini
Config choices: Version 1.1

Block 14 - Gemini Fallback Analysis 2

Type / Role: @n8n/n8n-nodes-langchain.lmChatGoogleGemini - lmChatGoogleGemini
Config choices: Version 1.1

Block 15 - Parse Structured Output

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

Block 16 - Validate Data with Code

Type / Role: n8n-nodes-base.code - code
Config choices: Version 2

Block 17 - Sticky Note4

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

3. Summary Table

Workflow	Validate bills of lading, send Gmail replies, and post JSON with Google Gemini
Complexity	advanced
Nodes	17
Categories	Document Extraction, AI Summarization
Author	David Grimm
Published	01 Jun 2026

4. Reproducing the Workflow from Scratch

1. Download the workflow JSON

Use the JSON export at /data/workflows/16049/16049.json as the source template for this automation.
2. Import the template into n8n

Open n8n, import the downloaded JSON, and review each node before activating the workflow.
3. Configure credentials and variables

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

Download workflow JSON Original n8n.io source Document Extraction workflows AI Summarization workflows

Frequently asked questions

What does Validate bills of lading, send Gmail replies, and post JSON with Google Gemini do?

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 Document Extraction, AI Summarization use case.

David Grimm

2 workflows

Nodes

n8n-nodes-base.stickynote n8n-nodes-base.gmailtrigger @n8n/n8n-nodes-langchain.googlegemini @n8n/n8n-nodes-langchain.agent n8n-nodes-base.httprequest n8n-nodes-base.gmailtool @n8n/n8n-nodes-langchain.lmchatgooglegemini @n8n/n8n-nodes-langchain.outputparserstructured

Complexity

advanced

Published 01 Jun 2026

Likes 0

View on n8n.io Download Workflow

Install path: /data/workflows/16049/16049.json

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Validate bills of lading, send Gmail replies, and post JSON with Google Gemini

Workflow preview

1. Workflow Overview

Best for

Tools used

Source and attribution

1.1 Workflow description

Quick overview

How it works

Setup

Customization

Additional info

1.2 Logical Blocks

2. Block-by-Block Analysis

Block 1 - Sticky Note

Block 2 - Sticky Note1

Block 3 - Sticky Note2

Block 4 - Sticky Note3

Block 5 - When Email Received

Block 6 - Analyze Document with Gemini

Block 7 - AI Document Analyzer Agent

Block 8 - Post to Webhook API

Block 9 - AI Validation Agent

Block 10 - Send Gmail Message

Block 11 - Gemini Main Analysis 1

Block 12 - Gemini Fallback Analysis 1

Block 13 - Gemini Main Analysis 2

Block 14 - Gemini Fallback Analysis 2

Block 15 - Parse Structured Output

Block 16 - Validate Data with Code

Block 17 - Sticky Note4

3. Summary Table

4. Reproducing the Workflow from Scratch

1. Download the workflow JSON

2. Import the template into n8n

3. Configure credentials and variables

4. Test with sample data

5. Activate and monitor

5. General Notes & Resources

Frequently asked questions