Embed the Subscribe Widget: Quick Start

The Subscribeam embed widget lets you drop a fully-branded subscribe form onto any website with a single <iframe>. It has no dependencies, sets no cookies, and is served from our CDN — so embedding it never slows your page down. This guide gets you from zero to a live form in a couple of minutes.

1. Create an application

Sign in or create a free account, open your dashboard and choose New app. An application stands for one newsletter: give it a name, and in Signup form URL enter the address your current signup form submits to (Substack, Beehiiv, Mailchimp and so on). Every sign-up the widget collects is forwarded there, so it lands on the list you already run. Email field name is the name of the email input on that form — usually email.

Each application has its own widget ID (written <newsletter-id> below) and its own appearance settings. The Free plan includes one application; Premium removes the limit.

2. Customise the appearance

Inside the application, open Design & embed. Set the colours or gradients, font, corner radius, heading and button text, and watch the live preview update as you go. When it looks right, save: the widget is re-published with your design straight away.

3. Copy the embed snippet

The application's overview and its Design & embed page both show a ready-to-paste snippet with a copy button. It looks like this:

<iframe
  src="https://cdn.subscribeam.com/embed/<newsletter-id>.html"
  width="100%"
  height="200"
  style="border:none"
  title="Subscribe to our newsletter"
></iframe>

Paste it anywhere HTML is allowed on your site. That's the entire integration — the widget renders your subscribe form and handles the signup for you.

Why it's served from a CDN

The widget HTML is pre-rendered and served from cdn.subscribeam.com, so pages that embed it never hit our application server. That means it loads fast and stays available even under heavy traffic. The older subscribeam.com/embed/subscribe?nid=<id> URL still works too — it simply redirects to the CDN version.

Good to know

• No cookies. The widget doesn't set cookies, so it won't complicate your consent banner.
• Responsive. Set width="100%" and the form adapts to its container.
• Auto-resize. The widget can report its height to the parent page via postMessage so the iframe can grow to fit its content — see Auto-resize & events.

Troubleshooting

• The form is cut off or leaves a gap. The iframe is as tall as its height attribute. Raise it, or let the widget report its own height — see Auto-resize & events.
• Nothing shows where the snippet is. Check that your editor kept the <iframe> as HTML rather than escaping it as text (in WordPress, use a Custom HTML block). If your site sends a Content Security Policy, its frame-src (or child-src) must allow https://cdn.subscribeam.com.
• A saved design change doesn't show. The snippet never changes, only what it loads. Reload the page bypassing your browser cache; a page cache or CDN in front of your own site may also be holding the old HTML.
• Sign-ups don't reach my email platform. Open the application's Subscribers page: each sign-up shows whether it was forwarded or failed. Failures usually mean the signup form URL or the email field name doesn't match the form your platform expects — compare them with the action and the email input's name on your existing form.
• Subscribers say they never got anything. Most platforms send a confirmation email before adding someone to the list. Ask them to check spam and promotions folders for a message from your newsletter.

Next steps

Using a specific platform? We have step-by-step guides for WordPress and for static sites and Ghost.