Why Litmus results may look different than local ones

There are a few common reasons why Litmus might show a different result to a result you performed manually (perhaps by opening the URL in a browser locally, or by sending the email to your own email client). In addition to OS, browser, and screen size, the email marketing platform the brand uses, the subscriber’s email client, and whether images are enabled or blocked dramatically affect email rendering. In all cases, Litmus uses the default or most common options and environments. This means you should assume that the Litmus rendering is the correct one. There are, of course, exceptions to this rule. Litmus may be showing an artifact of our testing software, but these are usually very obvious.


Mobile clients (iPhone, Android, etc.)

You may see differences with mobile clients due to the OS version, device, or email app you are using locally. The current device/OS settings we use for the mobile clients may be different than your local setup. 

We have also seen rendering differences in emails opened on Android if they are being sent through an Exchange server. You can read more about this in the Litmus Community here.

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Web-based email clients (Gmail, Yahoo! Mail, Outlook.com, etc.)

Web-based email clients borrow their HTML rendering capabilities from the browser hosting them. If you are using a different browser to manually test the email in your own web-based email account, try updating your browser version to the one used for the relevant Litmus preview client to see if the differences still exist.

Another important thing to consider is your own browser's settings. A common cause of rendering differences is font size. You should make sure that your browser's font size is set to "Normal". All Litmus browsers are set to "Normal", and are also viewed in 1366x768 resolution.

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Lotus Notes

Lotus Notes adapts its rendering depending on the source of the email. If a Domino server is used, it uses Internet Explorer to render the emails. If a POP or IMAP server is used, it relies on its own Rich Text view to render the email's HTML content. The only exception is Notes 8/8.5, which uses Explorer in either case.

Litmus currently uses the POP/IMAP approach for submitting tests to Lotus Notes clients.


Outlook, prior to Outlook 2007, used Internet Explorer to render an email's HTML content. If your version of Internet Explorer is different to ours, the email may render differently. Likewise, if your copy of Internet Explorer has unusual or customized settings, it may render differently to ours. These are the browsers we use with each version of Outlook:

Outlook 2000 Internet Explorer 6
Outlook 2002 Internet Explorer 7
Outlook 2003 Internet Explorer 7
Outlook 2007 Word 2007
Outlook 2010 Word 2010
Outlook 2013 Word 2013

Outlook for Mac 2011 uses WebKit to render emails, which does not rely on Internet Explorer or Word for rendering.

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DPI settings

Windows has an option to change your DPI settings for text, which can sometimes change the rendering within Outlook clients. By default, this is usually set at 96 DPI on Windows machines. Some users may change this to 120 DPI (or a custom number) for text for better readability. Microsoft's site has addition information on DPI settings. If you have a different DPI setting than the default selection of 96 DPI on your Windows machine, you may see some rendering differences locally due to your settings. We use the default DPI setting of 96 on all of our Windows machines.

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If Litmus is showing something different to your own local browser, there's a high chance it's to do with customizations in your local browser's settings. A common cause of rendering differences is font size. You should make sure that your browser's font size is set to "Normal". All Litmus browsers are set to "Normal". Try removing any debugging plugins such as Firebug that may be adjusting HTML or injecting Javascript.

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HTML-uploaded email versus ESP sent email

We highly recommend sending in your email directly from your Email Service Provider (ESP), as many times ESPs can change/alter your HTML template before your final send. Since Litmus does not alter your HTML code, you may see a difference between an HTML-uploaded copy versus what you see on your ESP's sent copy.

If you send in your email directly from your ESP, you will see exactly what your subscribers see when they receive your campaign. You can easily send in an email test to Litmus from your ESP by using Litmus' email addresses in the test/preview email send before sending your campaign to your subscribers.

Sending from your ESP is also best when using the spam filter analysis tools, as this will provide the most accurate reputation scoring for your email.

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Forwarded email sent for testing to Litmus

Forwarding your email test to Litmus is not recommended, as many times email clients (especially Outlook) can change/alter the HTML template on the forward. We recommend sending your test in directly from your ESP or the mailing platform you use to send emails to your subscribers.

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Table heights set to 100%

If any of the table heights are set to 100% height within your email, this can occasionally stretch your email out to the maximum screen capture height within our email clients. You may want to remove the height=100% within your email and retest if you are seeing stretched results for your email.


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