Importing Custom HTML

This guide explains how to import and use custom HTML code as your full email design in Sender’s Custom HTML email editor.

Where to Find This Feature

When creating or editing a campaign, navigate to the Design step. At the top of the design selection page, choose the Custom HTML email tab. This opens a full-screen code editor on the left with a live preview panel on the right. If you have already selected a design type, click Edit design on the Email campaign design page to reopen the editor.

You can also reach the editor from an existing draft by clicking the edit icon next to the campaign in Email campaigns, then clicking Design in the top navigation bar.

Steps to Import Custom HTML

Step 1 — Select the Custom HTML Email Editor

On the Design step of campaign creation, click the Custom HTML email tab at the top of the page. Sender loads a code editor pre-populated with a starter template that includes a  declaration, a

-based layout, and a {$unsubscribe_link} merge tag. The live preview panel on the right renders the default template immediately.Step 2 — Paste or Write Your HTMLSelect all the default code in the editor and replace it with your own HTML. Paste your complete email document, starting from  through . The live preview panel updates automatically as you type or paste. Use the + and − controls above the code editor to adjust the font size for readability.Step 3 — Import HTML from a URL (Optional)To pull HTML from an external source, click the Import from URL icon in the top toolbar (the downward arrow icon). In the Enter URL dialog, paste the full URL of your hosted HTML file and click Import. Sender fetches the HTML content from the URL and loads it into the code editor, replacing any existing code.Step 4 — Preview and Verify the OutputCheck the live preview panel on the right side of the editor. Toggle between Desktop and Mobile views using the icons in the top toolbar to verify rendering at both viewport widths. Review the Email size indicator in the upper-right corner — keep your HTML under 102 KB to prevent clipping in Gmail and other email clients.Step 5 — Save and Send a Test EmailClick the Save changes icon in the top toolbar to save your work. Then click Send test email to open the send dialog — enter a recipient address and click Send. Verify the rendering and link behavior in your inbox before proceeding. When ready, click Save and continue to advance to the Recipients step.Code Reference — Required as the first line of your imported HTML. Sender expects a complete HTML document structure with,, and elements.
layout — Sender’s default template uses nested elements with border=”0″, cellpadding=”0″, cellspacing=”0″, and width=”100%”. This table-based structure renders consistently across Outlook, Gmail, and Apple Mail.{$unsubscribe_link} — Sender’s unsubscribe merge tag. Place it inside an  tag’s href attribute (e.g., Unsubscribe) to generate a working unsubscribe link at send time.