Deliverability & the inbox
Inbox placement
Also known as: inbox rate · seed testing
The percentage of sent messages that landed in the Primary inbox vs Promotions tabs, spam folder, or were blocked entirely — measured via seed tests across real accounts at major mailbox providers.
Inbox placement is the percentage of a send that reached the Primary inbox rather than Promotions, spam, or outright blocks. Measured via seed tests: a panel of real email accounts (typically 50-150 seeds across Gmail, Outlook, Yahoo, Apple Mail, and international providers) that receive a copy of every send. Tools like Everest (ex-250ok), Validity, and GlockApps automate this. Inbox placement is the most accurate deliverability signal because it measures what actually happened, not what should have happened based on sender reputation. Healthy programs see 92-98% inbox placement globally; a drop below 88% typically indicates a reputation problem developing, and a drop to 75% is the red-alert threshold where immediate diagnosis is required.