How to Add a Widget to Substack
Substack prioritizes a focused, distraction-free reading experience. As a result, custom HTML and iframe embeds are not supported inside Substack post content — this is a deliberate platform restriction. However, you can still share Embeddy widgets effectively with your Substack audience using direct URL links, video demo embeds, or styled call-to-action text.
Substack blocks all custom HTML and iframes
Unlike platforms such as Bubble or Webflow, Substack does not provide an HTML element or any mechanism to insert arbitrary iframe code into post content. Code blocks in the Substack editor only display code as formatted text — they do not execute HTML or JavaScript. This applies to all Substack plans including paid publications.
1. How Substack Embeds Work
Substack supports URL embeds for a curated list of approved services. When you paste a URL from a supported platform on its own line and press Enter, it auto-embeds as a visual card. Supported services include:
Notably, general third-party widgets, CodePen, and custom iframe URLs are not on Substack's supported list. Substack also generates its own embed code (an iframe) that you can place on other websites to embed a Substack signup form — but this works in the opposite direction: from Substack outward, not inward.
2. The Limitation
You cannot paste iframe code into a Substack post
The editor will show it as plain escaped text, not as a rendered element.
Code blocks do not execute
Pasting <iframe> into a Substack code block displays it as formatted text only. It will not render the widget.
No custom CSS or JavaScript injection
Substack does not provide a way to add custom scripts or styles to post content at any subscription tier.
What you can do
Substack's reading experience is intentionally simple. The best strategy for sharing Embeddy widgets is to write a compelling call to action and hyperlink it to your widget URL. Readers who are engaged with your content will click through. Method 1 below shows exactly how to do this.
3. Method 1: Direct URL Link
The most straightforward approach is to hyperlink your CTA text to your Embeddy widget URL. When readers click the link, the widget opens in a new browser tab. This works in both the web version of your Substack and in email newsletters sent to subscribers.
- 1
Copy your widget's direct URL from Embeddy.
Go to your Embeddy dashboard, open your widget, and copy the direct URL from the Embed tab:
https://embeddy.ai/webhost/WIDGET_ID?widget_props_id=PROPS_ID - 2
Open your Substack post editor.
Navigate to the post where you want to reference the widget.
- 3
Write a compelling call-to-action sentence.
Write text that motivates readers to click. For example:
"Want to find out which pricing plan is right for you? Take the interactive quiz here — it takes less than 2 minutes."
- 4
Select the CTA text and add a hyperlink.
Highlight the clickable text (e.g., "Take the interactive quiz here"), then click the link icon in the Substack editor formatting bar (or pressCtrl+K). Paste your Embeddy widget URL and confirm.
- 5
Publish or send your post.
The link will appear in the web version of your post and inside email newsletters. Readers click the link to open the widget in a new tab.
Works in email too
Hyperlinks in Substack posts are preserved in the email version sent to subscribers. Your Embeddy widget link will appear as a standard hyperlink in your newsletter email, which readers can click from their inbox.
4. Method 2: Supported Embed Workaround
If your Embeddy widget has a visual or interactive demo that can be screen-recorded, you can embed a YouTube or Vimeo video showing the widget in action, then add a hyperlink below it inviting readers to try it live. This is the most visually impactful approach available on Substack.
Best for high-engagement posts
This approach works best for newsletters focused on showcasing products, tools, or interactive experiences. The video gives readers a preview of what the widget does before they click through.
- 1
Record a short screen capture of your widget in action.
Use any screen recorder to capture a 30–60 second demo. Show the widget's key interaction or output.
- 2
Upload the recording to YouTube or Vimeo.
Publish it publicly (or unlisted if you prefer) and copy the video URL.
- 3
Paste the video URL on a new empty line in your Substack post.
In the Substack editor, place your cursor on a new empty line, paste the YouTube or Vimeo URL, and press Enter. The video will auto-embed as a visual player.
- 4
Add a hyperlink below the video pointing to your Embeddy widget.
After the video embed, write a follow-up sentence with a hyperlink to your widget URL. For example:
"Try it yourself here — the live widget is free to use and takes under a minute."
5. Best Practices
Since Substack readers encounter your widget as a link rather than an inline embed, the quality of your call-to-action writing determines how many readers actually click through to use it.
Be specific about what happens when they click
Vague links like "click here" underperform. Tell readers exactly what they will see or do: "Take the 3-question quiz", "Generate your custom report", "Try the pricing calculator".
Mention the time commitment
Readers are more likely to click if they know it will not take long: "Takes under 2 minutes", "No sign-up required", "Instant results". This reduces friction and increases conversions.
Place the CTA after context, not before
First explain the value of the widget in 1–2 sentences, then present the CTA link. Readers who understand why the widget is useful are more likely to engage with it.
Consider a dedicated Substack button
Substack's editor supports a Button element (look for the + insert menu). Adding a dedicated button with your widget URL makes the CTA more visually prominent than a text hyperlink alone, especially for free newsletters where you want to drive engagement.
Use your Substack web post for hosting context
If you have a public Substack website (not just email-only), the web version of your post is indexed by search engines. A well-written post that references your Embeddy widget can drive organic traffic from readers who find the post via search.
6. FAQ
Will Substack ever support custom iframes?
As of 2026, Substack has not announced plans to support custom HTML or arbitrary iframe embeds in post content. Substack's product direction is focused on the writing and newsletter experience. If this changes, this guide will be updated. In the meantime, the link and video methods above are the recommended approaches.
Can I put an Embeddy widget on my Substack profile page or About page?
Substack's About page and profile sections also do not support custom HTML or iframes. You can add text and links but not embedded widgets. The best option is to include a compelling hyperlink to your Embeddy widget URL in your publication description or "About" section.
Can Substack readers access my Embeddy widget without leaving the newsletter?
Not directly from within the Substack interface — the widget will always open in a new tab when using the link method. For an in-page experience, consider hosting your Embeddy widget on your own website and linking to that page from Substack instead. This gives readers a dedicated, branded landing page for the widget.
Ready to share your widget on Substack?
Build and publish your Embeddy widget in minutes, then share it with your newsletter audience.