Best email client preview and testing tools

The long-standing standard. Widest client preview matrix, most mature pre-send checklist, and post-send analytics that show which clients actually opened. Pricing is enterprise-leaning, but the coverage justifies it for marketing teams.

Closest direct competitor to Litmus with broadly similar preview coverage. Generally cheaper entry price; campaign precheck bundles rendering, accessibility, links, and spam in one report.

Code-first email editor with live previews built in. Best fit when developers author HTML directly and want previews without leaving the editor. Owned by Litmus.

Staging inbox plus HTML preview and basic spam analysis. Strong fit when transactional QA matters more than marketing-grade client coverage.

Programmable inboxes with email rendering checks and device previews on paid plans. Better for automated test pipelines than for marketing review.