Build a Lead Magnet Signup Form with an AI Welcome Email

A free guide is one of the simplest ways a small business can grow its email list, but only if every signup gets the guide fast and a welcome that feels written for them. In this free lesson you build a "Get the free guide" form in Lovable and an n8n workflow where an AI agent tags each lead, saves it and emails the guide.

What you will build

You will build a lead magnet signup form for Harbor & Pine Coffee Roasters, a small online coffee brand used as the example. The form offers a free brewing guide called The Better Cup at Home and asks four things: name, email, what the person wants to improve and, optionally, how they brew now.

Behind the form is an n8n workflow. When someone submits, a webhook receives the data and an AI agent reads it. The agent tags the lead with one of four segments (New to Brewing, French Press & Pour-Over, Espresso at Home or Gift Buyer), adds a row to a Google Sheet called Leads, and uses Gmail to send a short welcome with the guide link and one tip that fits their segment. A Respond node tells the form it worked, and the visitor sees "Check your inbox!"

In the test, Jordan says their French press coffee tastes bitter and muddy. The agent tags Jordan as French Press & Pour-Over, saves the row and emails the guide with a tip for that brew method.

Who this is for

This is for small business marketers who have a guide, checklist or recipe card to give away and no time to send it by hand. It fits store owners, solo marketers and small teams who want every signup segmented from day one, without buying an email platform add-on to do it.

It is the most complete of the three marketing modules, because it joins a real web app to an AI backend. No coding is needed.

Step by step: what you do

• Build the form: start a Lovable project, paste the prompt that describes the signup form and its webhook, and build the app.
• Webhook trigger: start an n8n workflow with an On webhook call trigger, set to answer through a Respond node.
• AI Agent: add the agent, define its prompt manually with a template that pulls name, email, interest and brew method from the form, then paste the system message that lists the four segments and the rules for the welcome email.
• Chat model: connect OpenAI with your key and pick gpt-5-mini.
• Sheets tool: add Google Sheets, create a sheet named Leads with the headers Name, Email, Interest and Brew Method, sign in with Google, choose Leads and Sheet1, and let the model fill each column.
• Gmail tool: add Gmail and sign in so the agent can send the welcome email.
• Respond node and publish: add Respond to Webhook, then publish the workflow.
• Add the secret: copy the production webhook URL and save it in Lovable as a secret, so the URL is never hard-coded in the page.
• Test the form: fill it with test data, click Send Me the Guide, and check the new row in the spreadsheet.

Why it works

Most signup forms treat every lead the same. Here the two questions on the form give the agent something to work with, and the system message turns that into a clear segment and a relevant tip. The person gets a welcome that answers the problem they just told you about, and you get a list you can already sort.

The pieces each do one job. Lovable builds the page. The webhook receives the data. The agent decides the segment and writes the email. Sheets keeps the record and Gmail delivers it. Because the webhook URL is stored as a secret, you can change the workflow later without touching the form.

How to use this in your business

Replace the brewing guide with your own lead magnet and rewrite the two questions so the answers tell you something useful, like what a visitor wants help with and where they are starting from. Then rewrite the segments in the system message to match how you actually market: by product line, by experience level or by buyer type.

Once it is running, sort the Leads sheet by interest to plan your next emails, and use the segments to decide who hears about which product first. Keep the rules in the system message strict: no discounts you do not offer and no claims you cannot back up.

What you need

• For the practice copy here: nothing. No form is published and no email is sent.
• For the real build: a Lovable account, an n8n account, an OpenAI account with a little credit, and a Google account for Sheets and Gmail.
• A guide to give away, saved somewhere you can link to it.

Frequently asked questions

Is this course really free?

Yes. Stepthrough is completely free, and the practice copy needs no accounts. To build it for real you need your own Lovable, n8n, OpenAI and Google accounts, and some of those cost money once you use them for real work.

What is a lead magnet?

A lead magnet is something useful you give away, like a guide or checklist, in exchange for an email address. In this lesson it is a free coffee brewing guide.

Can n8n send a personalized welcome email with AI?

Yes. In this lesson the n8n AI Agent reads each signup, picks a segment and uses the Gmail tool to send a short welcome with the guide link and a tip that fits that segment.

Where is the lead's segment stored?

The sheet saves what the person typed: name, email, interest and brew method. The agent uses those answers to choose the segment for the welcome email. You can add a Segment column when you build it for real.

Do I need to know how to code to build the form?

No. Lovable builds the form from a written description, and n8n is set up by clicking nodes and pasting prompts. The lesson walks you through every click.

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