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Minify Your Emails To Improve Deliverability & Engagement

Based on research by Email on Acid, the overall size of your email’s HTML can have a big impact on the deliverability and performance of your email. Sending an unnecessarily large email:

  1. Has a higher risk of being classified as spam
  2. Can be truncated by some email clients
  3. Loads slower and risks instant delete from impatient recipients

One of the safest and easiest ways to minimize these risks is to minify your HTML before you hit the Send! button. Hand-crafting an email with its myriad of deeply-nested tables, redundant inline styles and endless workarounds typically require the astute coder to use excessive indentation and comments to maintain sanity. But all that extraneous whitespace is slowing your email down and driving down your recipient engagement.

Here’s a concrete example. In this Litmus Community post, an email coder posted his heavily-indented email source which weighs in at 27k. Running the code through a free online HTML minifier removes more than 10k of whitespace and comments — making the email 37% smaller.

Furthermore, according to Litmus, “51% of recipients delete your email within two seconds of opening it.” That timer begins the moment the recipient opens your email. The faster your email loads and renders, the less likely it is your email will be instantly deleted.

Minifying your email HTML should be critical item on your preflight checklist. That’s why it’s one of the key features of Inkcite, our free and open-source email workflow. When you run inkcite build to produce ready-to-send markup, Inkcite automatically minifies your HTML, CSS and inline styles. (Inkcite also wraps excessively long markup to a reasonable length because, in our tests, some versions of Outlook introduce rendering problems when lines exceed a certain character count.) Learn how to install Inkcite and make your first email project.

Also, although Email on Acid notes that image size does not affect deliverability, bulky, slow-loading images will have a negative impact on engagement. Inkcite will automatically optimize and compress all of the images in your project. Learn more about Inkcite’s automatic image optimization.

Don’t make this easily avoidable #EmailMistake — minify your HTML and optimize your images to reduce the risk that your email will be marked as spam or instantly deleted.



Tips for coding engaging, responsive emails with modern tools by the creator of Inkcite, the modular design system for modern, responsive email development. #emailgeek #MakeEmailBetter

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Jeffrey Hoffman

Jeffrey Hoffman

Pretty good at writing the best. code. ever.