Litmus from Validity

Litmus from Validity is the email testing and analytics workbench used by marketers, designers, and developers to preview how campaigns render across 100+ email clients and devices, run spam tests, and analyze performance after send. TrustRadius scores it 8.9/10 across 588 reviews: reviewers love the rendering previews and analytics, but the high price tag and the removal of the free plan are the recurring complaints.

What is Litmus from Validity?

Email is the hardest marketing channel to build for: every client renders HTML differently, and what looks perfect in Gmail can break into a mess in Outlook. Litmus is the tool the industry built to fix that. Marketers, email designers, and developers use it to preview campaigns across 100+ clients and devices, run spam tests against 25+ filters, automate QA on broken links and missing images, and — after send — read accurate analytics with reliable open rates, dark-mode tracking, and read-time data. Under Validity, it has expanded beyond testing into deliverability and proofing workflows. The 8.9/10 score across 588 TrustRadius reviews reflects a product reviewers genuinely like: the previews catch real problems, the QA automation saves hours, and the integrations with every major ESP (Salesforce Marketing Cloud, Adobe Campaign, Braze, and more) slot it cleanly into existing stacks. The complaints are almost entirely about money. Litmus starts around $99/month and scales with email volume and seats, the once-free basic plan is gone, and several of the most useful features — advanced analytics, spam testing, collaboration — live in higher tiers. It is also a test-and-measure layer, not an ESP: you still pay for sending elsewhere. For teams that send enough email for a broken layout to cost real money, Litmus pays for itself. For small senders, cheaper tools cover most of the ground.

Key Features

• *Email previews** — See exactly how campaigns render across 100+ email clients and devices before sending
• *Spam testing** — Test against 25+ spam filters to flag deliverability problems pre-send
• *QA automation** — Automatically scan for broken links, missing images, and tracking issues
• *Email analytics** — Post-send metrics with reliable open rates and dark-mode usage tracking
• *Litmus Builder** — Visual email editor with reusable code snippets and instant previews
• *Templates** — Customizable, tested email templates to speed up campaign creation
• *Litmus Proof** — Centralized feedback, comments, and approvals to save hours per email
• *Litmus Personalize** — No-code interactive content: live polls, countdown timers, personalized images
• *Integrations** — 20+ ESP integrations including Salesforce Marketing Cloud and Adobe Campaign
• *Deliverability tools** — Inbox-placement insights and sender reputation help under the Validity umbrella

Who is it for?

• Marketing teams that send high-volume, high-stakes campaigns where broken renders cost money
• Email designers and developers who need reliable cross-client previews
• Agencies managing email for multiple clients who want QA and proofing in one place
• Teams already on major ESPs who want a testing and analytics layer on top

Who is it NOT for?

• Small teams and solo senders — the price starts around $99/month and there is no free plan
• Anyone expecting an email service — Litmus tests and analyzes but does not send
• Budget-conscious marketers who only need basic previews — cheaper tools cover it
• Teams on entry-tier plans who want advanced analytics and spam testing — those are gated