Litmus pre-send testing Checklist guide

Use the Previews & QA automated pre-send testing checklist view of your email to gain confidence before you send it. This pre-send testing checklist helps make 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, confirm emails are accessible to every subscriber, and more—all before pressing send.

Note: In the Legacy version, this pre-send testing checklist is called "Litmus Checklist" and it is a stand alone tool. In the New Litmus Platform Checklist is now labeled "Previews & QA" and is integrated into the email views with Builder, Summary, Proof, and Analytics. 

Getting started - Send or Create an email in Litmus 

Your Previews & QA pre-send testing checklist processes your email by reading all the elements of it and rendering email client previews.  To create a pre-send testing checklist you need to send in or upload your email.  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 automated pre-send testing checklist: 

Click on the "Previews & QA" tab to view your pre-send testing checklist. There are eight sections; the sidebar shows the number of warnings in each section. 

pre-send testing checklist

Navigating the pre-send testing checklist

Scroll through the entire checklist or 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.

There is a "Comparison View" option, so you can preview your 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. This option is available through the "Flag this for review" button in the lower right-hand corner of your screen or underneath each of the preview thumbnails. There is also an "Edit Code" button which will bring you straight into a new Builder project so you can inspect and edit the code.

For some email clients, there is a "Toggle images off" button to see how your email will look with images off for that client. 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 check mark.


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, as well as 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. 

Note: 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. 

Starting a Checklist in Legacy Litmus

In Legacy Litmus you can start a new Checklist from the Dashboard using the Quick Start options or you can find Litmus Checklist in the left side navigation bar. 

Dashboard View

In the Checklist section of Legacy Litmus You’ll see some options along the top of the page, that let you toggle between “All Checklists” from your team, and “My Checklists” which were run under your own personal login. You’ll also be able to sort by time, organizational tags, and by Checklist name. 


Starting a new Checklist

To kick off a new Checklist, simply click on the green “Start a new Checklist” button in the upper right-hand corner of your screen. 

Start a new Checklist

This will prompt you to create a static Litmus test address where you send in your email from your email service provider. You’ll then see your email displayed on the dashboard. Once you open your Checklist, you'll be walked through a series of checks to ensure that your email is ready for the final send.

Once you have created your Litmus test address, you can simply send your email to this address and a new Checklist will be automatically created for you. You don't need to manually start one each time—unless you want to of course!

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