Glossary · Marketing, CRM & Growth
Litmus
Overview
What Litmus is
Litmus is a subscription-based email testing and analytics platform used by marketers, developers, and agencies to preview and validate email campaigns before sending. Founded in 2005, it is best known for its rendering previews, which show how a single email will display across a wide range of inboxes, apps, and devices.
The product spans three areas: Test (rendering previews, spam checks, and link validation), Track (post-send analytics on how emails were opened), and Build (an editor for authoring and reusing email code). More recent additions include authentication monitoring and personalization features.
How Litmus works
You paste your email HTML or connect your email service provider (ESP), and Litmus generates screenshots of the email as rendered by real email clients such as Outlook, Gmail, Apple Mail, and mobile apps. It also flags likely spam triggers, broken links, and missing alt text, and checks accessibility factors.
After a campaign sends, Litmus Email Analytics uses a tracking pixel to report which clients and devices recipients used, engagement by geography, and read time. It integrates with major ESPs including Salesforce Marketing Cloud, Marketo, Mailchimp, and Klaviyo.
Why Litmus matters
Email clients render HTML inconsistently, so a design that looks correct in one inbox can break in another. Catching those issues before sending protects brand credibility and conversion rates, especially for large lists where a rendering bug can affect thousands of recipients at once.
Litmus is a paid tool; its main competitor is Email on Acid, and open-source frameworks like MJML reduce (but do not eliminate) rendering problems at the code level. Teams often pair a testing platform with careful coding rather than relying on either alone.
Where we use it
Related Zen in Tech services
How our team puts Litmus to work in real projects.
FAQ
Litmus — common questions
What is Litmus used for?
Litmus is used to preview how an email renders across many email clients and devices before sending, and to analyze how recipients engaged after the send. It helps catch display bugs, spam issues, and broken links early.
Is Litmus free?
No. Litmus is a paid subscription platform with tiered plans, though it typically offers a limited free trial. Email on Acid is its closest paid alternative.
What is the difference between Litmus and MJML?
Litmus is a testing and analytics platform that shows how finished emails render, while MJML is a free markup framework that generates responsive email HTML. They solve different parts of the workflow and are often used together.
Need Litmus done right?
Book a free consultation and we’ll map the fastest, most cost-effective path for your project.
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