N8N: Visual Workflows with AI Nodes

You build an AI workflow in N8N that automatically processes data and executes actions.

Why this lesson matters

Custom GPTs are handy, but they only work inside ChatGPT. What if you want an agent that responds automatically to an incoming email, a form or a webhook? Then you need a workflow tool. N8N is the most powerful open-source option: free, self-hosted, and with built-in AI nodes.

In this lesson you get to know N8N and build a workflow in which AI automatically classifies emails and forwards them to the right department.

What is N8N?

N8N (pronounced "n-eight-n") is an open-source workflow automation tool. Think Zapier, but:

Free if you host it yourself
Visual: you build workflows by dragging and connecting nodes
Strong: more flexibility than Zapier or Make
AI-native: built-in nodes for OpenAI, Anthropic, and a dedicated AI Agent node

Going deeper

N8N also has a cloud version if you don't want to self-host. That starts at $20/month. The self-hosted version is completely free and runs on any machine with Docker.

Basic concepts

text

┌──────────┐    ┌──────────┐    ┌──────────┐
│ Trigger  │───→│  Node 1  │───→│  Node 2  │
│ (start)  │    │(process) │    │ (action) │
└──────────┘    └──────────┘    └──────────┘

Concept	Explanation	Example
Node	A building block that does 1 task	Fetch an email, analyse text
Connection	The arrow between nodes	Data flows from left to right
Trigger	The start node -- what kicks off the workflow?	New email, webhook, schedule
Credentials	Login details for external services	Gmail password, OpenAI API key
Execution	One run of the workflow	Every incoming email = 1 execution

AI nodes in N8N

N8N has dedicated nodes for AI:

OpenAI node: Send a prompt to an OpenAI model and get an answer back. Handy for classification, summaries, translation.

Anthropic node: The same, but with Claude. Often better for longer texts and analyses.

Keep reading

Leave your name and email address and you can read the rest

You get the whole lesson right away, and every other lesson stays open after that. No password, no confirmation email.

AI Agent node: This is the most powerful one. With it you build a complete agent that:

Has a system prompt
Can use tools (other nodes)
Decides for itself which tool to use
Can run through several steps

Tip

The AI Agent node in N8N is in fact the ReAct pattern from lesson 2, but visual. You attach tools (other nodes) to the agent, and it picks for itself which one to use.

Example: email classification and routing

Let's build a concrete workflow:

Goal: Automatically classify incoming emails and forward them to the right department.

text

┌─────────┐   ┌──────────┐   ┌──────────┐   ┌──────────┐
│ Gmail   │──→│ OpenAI   │──→│  Switch  │──→│ Slack/   │
│ Trigger │   │ Classifi-│   │  (route) │   │ Email    │
│         │   │ cation   │   │          │   │ Output   │
└─────────┘   └──────────┘   └──────────┘   └──────────┘

Step 1: Gmail Trigger

Set the trigger to "New email in inbox". The node automatically fetches the sender, subject and body.

Step 2: OpenAI classification

Send the email body to the model with this prompt:

text

Classify the following email into exactly one of 
these categories:
- SALES (questions about products, prices, quotes)
- SUPPORT (complaints, problems, returns)
- ADMIN (invoices, contracts, administrative)
- SPAM (unwanted, not relevant)

Email:
{{$json.body}}

Answer with the category only, no explanation.

Step 3: Switch node

Based on the classification (SALES, SUPPORT, ADMIN, SPAM) you route to different outputs.

Step 4: Action per category

SALES → Slack message to #sales-team
SUPPORT → Create a ticket in the helpdesk
ADMIN → Forward to administratie@bedrijf.nl
SPAM → Archive and ignore

Watch out

Test your classification prompt thoroughly before you switch the workflow on. Send 20-30 test emails with different subjects and check whether the classification is right. Adjust the prompt until you're above 90% accuracy.

N8N vs Zapier vs Make

	N8N	Zapier	Make
Price	Free (self-hosted)	From $20/month	From $9/month
AI nodes	Extensive (Agent node)	Basic (AI actions)	Good (OpenAI module)
Complexity	Medium	Low	Medium
Flexibility	Very high	Limited	High
Self-hosting	Yes	No	No
Number of integrations	The fewest	The most	Many
Writing code	Yes (JavaScript)	Limited	Limited

Installing N8N

The fastest way to start N8N:

text

# With Docker (recommended):
docker run -it --rm \
  --name n8n \
  -p 5678:5678 \
  n8nio/n8n

# Or with npm:
npx n8n

Then go to http://localhost:5678 and you can start building.

?Knowledge check

What makes the AI Agent node in N8N special compared with a regular OpenAI node?

?Knowledge check

What is the biggest advantage of N8N over Zapier?

?Knowledge check

In the email classification workflow, what does the Switch node do?