Testing HTML emails efficiently as possible

Recently, I talked about the pros and cons of sending HTML vs Text emails to your clients in this article “Filling your inboxes with visual appealing HTML emails”. Since HTML Emails are becoming increasingly more popular to send here at Wayne State, we are trying to come up with a system that makes this painstakingly clumsy process as streamlined as possible.

Third party testing

If you have one main template and don’t have to create new ones often, a pay email testing service might be for you. For a small fee you can use one of these services to send your HTML code to and then it will produce screenshots of how the email looks in the most popular email clients. In addition, some of these services will also test how your email will react with spam filters.

Pay for testing resources

screenshot inbox inspectorlitmus email screenshotscampaign monitor email screenshots

Testing in house

If you don’t have the resources or funding to go with one of the automated services, you can go the “old fashioned way” and set up a series of test email accounts on all the popular email clients. To begin with, set up accounts on Hotmail, Yahoo, Google, AOL and of course, Outlook 2000, 2003, 2007 and Outlook Express. Don’t forget to test Apple Mail 2 and 3 and to test on the iPhone as well. This will get you tested in over 80% of all the popular email clients, according to Campaign Monitor as of June 2009, in their article Email client popularity.


Don’t forget to test email in popular mobile environments as well, iPhone for example is now more popular than gmail in viewing email. Once you establish some main HTML email templates the testing will get easier. When designing email templates, keep it simple. Trying too much, is one of the biggest mistakes designers do when creating HTML emails.

Here are some more good resources for getting a professional and cross-platform HTML email below. Remember to test, test, test!

Free HTML testing resources

Other resources and HTML email information

2 Replies to “Testing HTML emails efficiently as possible”

  1. CampaignMonitor’s stats are useful, but keep in mind they reflect a worldwide audience. Sometimes there can be regional spikes in e-mail clients. Certain geographic areas may have a lot of users who check their e-mail on the Web using their ISP, i.e. Comcast, Charter, etc. Test what *your* recipients are likely using.

    And, much like testing Web pages, how an HTML e-mail displays in Yahoo, Gmail, etc., can vary between Web browsers (Firefox, IE6, IE7, Safari, etc.). Then there is Yahoo Mail vs. Yahoo Classic, different versions of Gmail…

    BTW, CampaignMonitor and MailChimp both use an integrated ReturnPath tool for their testing, though they charge different amounts last I checked. Other e-mail service providers (ESPs) also offer render testing services through this third-party approach or through home-built tools. Shop around for pricing.

    Pivotal Veracity, a company that competes with ReturnPath, also offers a rendering tool.

    Email on Acid offers a free render testing tool, though it is an emulator as opposed to live screenshots. At the very least, it is a good reminder of what your e-mail looks like with images off, which is how most people will see it.

    Some alternatives to Premailer for placing CSS inline (if you use CSS for e-mail) include Emogrifier and Inline styler. CampaignMonitor is generally considered to have the definitive guide to CSS support in e-mail clients. If you can get a CSS-based e-mail to work in Gmail and Outlook 2007/2010, the rest *usually* fall into place.

    Don’t overlook a table-based design, though. They generally present few problems with e-mail clients. If you ignore Lotus Notes, you can nest at least 15 tables. With Lotus Notes, up to 8. More info… Imagine the design possibilities with 8 or more nested tables.

    And, of course, don’t overlook W3Cs markup validation tool. Validate your code, even for e-mail.

    Much like Web design, e-mail design and marketing is a niche area (arguably, areas) of expertise. And much like Web design, a person can make use of the tool without much expertise and obtain benefits, and keep learning more to reap more benefits 🙂

  2. Hi Rob,

    Enjoyed reading the article. I’m confused about the comment that “iPhone for example is now more popular than gmail in viewing email.” The graph for the article (which is Wayne State only) shows that gmail has a higher readership than combined iPhone 2.0 and 3.0.

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