Litmus pre-send testing Checklist guide

Use the Previews & QA section to view the results of your Litmus Test, an automated pre-send checklist of your email, and gain confidence before you send it. The Litmus Test makes sure every email you send is error-free.  With pre-send testing in Litmus, you can preview your email in 90+ apps and devices, validate your links, images, and tracking, test your email's load time, run spam tests, confirm emails are accessible to every subscriber, and more—all before pressing send.

Note: This pre-send testing checklist used to be called "Litmus Checklist" and was a stand-alone tool. Checklist is now labeled "Previews & QA" and is integrated into the email views with Summary, Builder, Proof, and Analytics. 


Getting started - Send or Create an email in Litmus 

Emails in Litmus have a Previews & QA section where you will see your Litmus Test results. To get started with a Litmus Test you first need to create a new email by sending in or uploading the email you want to test. There are many ways to do this:

  • Send an email draft from your ESP to your personal Litmus email address.  This will put the email into the Unsorted Emails view.
  • Sync from your ESP (available on Plus and Enterprise only).  This option also sends into Litmus but uses an API connection to do so.
  • Paste your HTML
  • Send your HTML from Builder via the "Update Proof & Previews" (or "Update Previews" for customers without Proof) action
  • Import an HTML file from a file sharing service (Dropbox, Drive, Onedrive)

Creating your Email in Litmus

See this detailed guide to Creating an Email in Litmus for more information on the above methods.  To get started quickly: 

  1. Navigate to any folder in Litmus
  2. Click "New Email"
  3. Enter a title and click "Test" 
  4. Choose an option to start testing your email.

Note: We recommend you send a draft email in or Sync from ESP for the most accurate previews and results.

Enter a title and click "Send or import your email" under the "Test" workflow:

create a new email

Choose an option for creating or importing your email:

start a new email test

The sections of your Litmus Test: 

Click on the "Previews & QA" tab to view your Litmus Test results. There are eight sections, starting with Previews. 

previews section

Navigating the pre-send testing checklist

Scroll through the entire Litmus Test or use the sidebar to navigate.  The red numbers are the number of warnings in each section. use the navigation on the left side. If we found an issue we will highlight that in the left side section headings.   

Below are descriptions of each of the eight sections. 


The first section you’ll see is your Email Previews. Similar to Builder, you can test your email across your selected email clients to help you find and correct rendering issues before you hit send, making sure your email looks good and works great everywhere. Full-length previews are visible in this section and can be selected to see a larger view.  

Use the filters at the top to quickly jump to a specific preview or to sort the previews by popularity.  The popularity sort will use the last 180 days of your data from Litmus Email Analytics to sort the previews in order most opened by your subscribers. 

preview filter

There is also a filter to only show the "flagged" email previews. Each preview has a flag that can be clicked to indicate it needs review.  This option is available underneath each of the preview thumbnails and in the lower right-hand corner of the full-screen view of the email preview. 

When in the full-screen view, there is a "Comparison View" option, so you can preview screenshots side by side. You'll find this option in the upper right-hand corner after you select a screenshot to enlarge it. You can toggle between the "Comparison View" and the "Detail View" as needed.

While viewing your screenshots, you can also flag any emails needed for review. There is also an "Edit Code" button that will open a new Builder view so you can inspect and edit the code.

There is a "Toggle images off" button for some email clients to see how your email will look with images off. There is also a "Recapture image" option if required.

First Impressions

The next section you'll review is First Impressions, where you’ll find checks for your Subject Line, From Name, Reply-to address, and Preview text. If we detect any errors in these categories, we'll suggest a fix for you. Otherwise, you'll just see a green checkmark.


The Accessibility section will identify any areas of code that need attention and provide line numbers to help locate Alt-Text, Headings, Text Justification, and your table tags (for the table role check). There will also be guidance included on how to fix your HTML to create emails accessible to all subscribers.

Litmus is also the only platform that allows you to listen to an audio recording of your email and download a transcript to understand how a screen reader would relay it to a subscriber with a visual impairment.


We'll also check to make sure your links are working correctly. You'll be able to see your link text and path for each URL. Our check is comprehensive and includes a visual preview of the link, running the link against the Google Safe Browsing database to check for suspected phishing and malware pages, and verifying that click-throughs are being tracked. We’ll even expose Google Analytics UTM parameters if you’re using them on links in your email.

Tracking Check

The Tracking Check section will ensure that your clickthroughs are being tracked by your ESP and/or Google Analytics. We'll also let you know if a Litmus tracking code was included in your email.

Image Blocking Check

With so many email clients blocking images by default, and some subscribers choosing those settings on their own, image blocking is unavoidable. Luckily, you can earn a competitive edge in the inbox by using techniques like alt text and background colors so your email can remain legible in all circumstances.

Loading Speed Check

Loading Speed Check will show you how many images are in your email, the total size of all of the images included in your email, and of course, the total time it takes for all the images in your email to load. You can also see the size of each individual image and how long each took to load. We’ll also identify any broken images with a red X and you can click through to see each one.

Spam Testing

If you send an email into Litmus or use the ESP sync option to start your pre-send email test, then Litmus will automatically run a set of Spam tests. 

spam testing

Note about Spam tests: If you have pasted the HTML or sent from Builder to Previews & QA via the "Update Proof & Previews" button (or "Update Previews" for customers without Proof) action, we can't run spam tests. Spam tests are dependent on the sending domain for accurate results. In these cases, you are prompted to start a Spam test in the Spam test section of Litmus. 

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