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Best Practices for Blast HTML Uploads
Best Practices for Blast HTML Uploads
Robert Lanckton avatar
Written by Robert Lanckton
Updated over 10 months ago

Broadcast sends all Blasts created in our editor in an HTML Format, with our own code, including the ability to change your view on Desktop and Mobile, and store images with us. However, you can also upload your own HTML Blasts to the Blast editor if you want more control over certain Blasts.

Getting Started

All the preparation of your Content is done in your own code first. After uploading the HTML, the content of your upload will not be editable. The Blast subject line and audience information are configurable for all Blasts.

Before you begin creating your email, it is important to familiarize yourself with HTML email best practices. These can help ensure that your email will be displayed correctly across different email clients and devices. Some popular email clients include Gmail, Yahoo Mail, and Outlook.


After uploading your HTML to the Blast editor, you'll see a preview of your Blast set to 600 Pixels wide. This may not look as expected, depending on the variation of your code from standard HTML. To test how your Blast will look in your email clients or specific configurations, you can Send a Sample right from the Blast editor.

Best Practices

Here are a few things to keep in mind when using the HTML upload option for Blasts.

  • HTML Emails should be designed with older versions of web browsers and email clients as well as modern experiences. Email clients do not support modern HTML practices utilized on many current web pages.
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  • Emails should be 600 pixels maximum width. This will make them behave better within the preview-pane provided by many clients.
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  • Design for simplicity. Use table based code and do not use complicated elements that require HTML floats or positioning.
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  • Images must be self-hosted and referenced to their full path URL on your server.
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  • Assume images will be initially blocked by email clients, or that certain images—background images, for example—will completely fail to load.
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  • Don’t design a Blast that’s one large, sliced up image as it is difficult to guarantee positioning across all email clients.
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  • Use cross-platform fonts like Arial, Verdana, Georgia, and Times New Roman.
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  • Do not use JavaScript. If you need motion in an email, .gif images are supported.
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  • Don’t forget about mobile! Is your email readable on a small screen? Will images slow load times on a mobile device? Are your links easy to access?

Download a Blast as HTML to Learn More

Not super familiar with HTML Email standards, but want to learn how we build our Blasts? Create or open a Blast in our Blast editor, then select the Ellipsis menu to Download as HTML for review in your own HTML editor.

If you have any questions at all, please don't hesitate to reach out to us at support@cerkl.com or use the support Chat toward the bottom right-hand corner of any cerkl.com page.

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