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Forms and growth

Lead magnets and signup forms

Collect subscribers on your site with a lead magnet or a signup form. Every signup confirms by email first.

Lead magnets

A lead magnet is a free resource, like a PDF guide, offered in exchange for an email. Create one with the onboarding. Then manage it in Lead magnets. Each lead magnet has a public page at /l/<slug>. In the editor, you change the badge, title, subtitle, button and legal note. A live preview shows phone, tablet and desktop.

To add it to your site, paste the snippet from Install on your site:

<script src="https://smartletter.ai/embed.js" data-slug="my-lead-magnet"></script>

Pick the Integration mode:

  • Inline iframe: the form shows where you paste the script. Free on every plan.
  • Exit-intent popup: opens when the mouse leaves towards the top of the page.
  • Sticky banner: a bar at the bottom of the page.
  • Delayed popup: opens after a few seconds.
  • Scroll popup: opens after the visitor scrolls part of the page.

WordPress plugin

  1. In the lead magnet, open the WordPress plugin tab and click Download plugin (.zip).
  2. In WordPress, go to Plugins, then Upload, and pick the .zip.
  3. Click Install, then Activate.
  4. Open Settings, then Smartletter, to check the connection.

No code to paste. The plugin knows your lead magnet and uses the mode you picked.

Each download creates a new token. The old plugin stops working.

Newsletter signup form

A simple form to join a newsletter, with no lead magnet. In Newsletters, pick a newsletter and open Signup form.

  • Title, short description and button label.
  • Accent color.
  • A first name field, shown or not.
  • Custom fields: only those marked "shown in signup forms" on the Fields page. See Contact fields.
  • Display mode for the script: the same 5 modes as lead magnets.
  • Allowed sites: up to 10 domains. The form only works on those sites. Empty means any site.
  • Redirect URL after signup (plain HTML version only).

The page shows a live preview and copy buttons for both versions.

Add the form to your site

Option 1, the script. It shows the form in a frame that adjusts its height. An invisible Cloudflare check blocks bots.

<script src="https://smartletter.ai/embed.js" data-form="FORM_ID"></script>

Option 2, plain HTML. Copy and paste the form. It works without JavaScript and uses your accent color. A hidden trap field, an origin check and limits per visitor and per form block abuse.

Using an AI assistant? The MCP tool signup_form.get returns both snippets. See API and MCP.

What happens after a signup

Every signup is double opt-in. The contact gets a confirmation email. They stay pending until they click the link.

The visitor sees a "check your inbox" message. For Gmail, Outlook, Hotmail and Live addresses, an Open Gmail or Open Outlook button is shown.

  • A typo in the domain, like gmial.com, gets a "did you mean" suggestion.
  • Spam traps, disposable addresses and domains with no mail server are dropped. The visitor sees the same message.
  • Someone who had unsubscribed, or a dormant contact, must confirm again by email.

Lead magnet confirmation links expire after 7 days. A contact gets at most one confirmation email per hour.

Archive signup form

Your public archive has its own Subscribe form on each page. You can also offer it in a pop-up, halfway through an issue. Turn this on in the Public archive panel of Newsletters.

It follows the same rule: the reader confirms by email first.