Testing
Litmus
Email client previews and pre-send QA across 100+ inbox environments.
overview
Litmus is the long-standing standard for previewing how a marketing or transactional email actually renders across Gmail, Outlook, Apple Mail, mobile clients, and dark-mode variants. Pre-send checklist catches broken links, missing alt text, spam triggers, image weight, and load time. Build, Proof, and Analytics modules cover authoring, review, and post-send heatmaps.
deliverability
Not applicable; preview and QA, not a sender.
best for
Marketing and lifecycle teams that need pixel-accurate previews across every major client before sending.
not great for
Solo developers sending only plain-text or simple transactional email.
pros
- › 100+ real client previews including the hard ones (Outlook desktop, dark mode, mobile)
- › Pre-send checklist catches rendering, accessibility, and spam-trigger issues
- › Post-send analytics shows which clients and devices actually opened
cons
- › Pricing is enterprise-leaning and not transparent on higher tiers
- › Overkill for teams sending only plain transactional email
- › Builder is separate from your sending platform, so workflow has handoffs
Features at a glance
| API | Yes |
| SMTP | No |
| SDKs | None |
| Webhooks | Yes |
| Templates | rich |
| React Email | No |
| Batch send | No |
| Scheduled send | No |
| Suppressions | No |
| Multi-tenant | Yes |
| Inbound parsing | No |
| Event stream | No |
| Idempotency keys | No |
| Dedicated IP | No |