What is seed list testing for inbox placement?

Seed list testing involves sending your message to a panel of test addresses maintained at various mailbox providers. By checking where these test messages land, you measure actual inbox placement rates.

Services like GlockApps, Validity (Everest), and 250ok maintain seed lists across major providers including Gmail, Outlook, Yahoo, and others.

After sending to the seed panel, the service reports where each message landed: inbox, spam folder, or missing (blocked). This shows your real-world deliverability before hitting your actual list.

Seed testing has limitations. Test addresses do not have the engagement history of real subscribers, so results may not perfectly predict actual performance. However, it provides valuable directional information.

Seed testing is sending scout ships ahead to check which harbors are open. Their report informs your strategy for the main fleet.