Seed list placement tests
How daily seed tests work, what they measure, when they fire alerts.
On this page · 3
- How the test runs
- What gets surfaced
- When alerts fire
Seed list testing is the only direct way to measure inbox placement. Inboxlee runs a daily test on every live mailbox against a 24-mailbox seed list spread across Gmail, Workspace, Outlook, M365, and Yahoo.
How the test runs
Once per day, each mailbox sends a probe to the seed list. The seed list inboxes are monitored, and we record where each probe lands - primary, promotions, spam, or missing entirely.
The probe is unobtrusive: a short, generic message with no links or images, sent at off-hours so it does not interfere with your real campaigns. It does not count toward your daily send limit.
What gets surfaced
When alerts fire
Default thresholds: alert if primary placement drops below 75% on any individual mailbox for 2 consecutive days, or if cohort-wide placement drops more than 15 percentage points week-over-week. Configurable in Settings → Notifications.