Deliverability & the inbox
Google Postmaster Tools
Also known as: Postmaster Tools · GPT (Gmail)
Gmail's free dashboard exposing per-domain reputation, spam-rate, authentication pass rates, delivery errors, and IPv6 reputation — the only direct window into how Gmail currently scores your sending.
Google Postmaster Tools is a free dashboard at postmaster.google.com that surfaces Gmail's own measurement of your sending performance. Metrics exposed: domain reputation (High, Medium, Low, Bad), IP reputation (per sending IP), spam rate (per-day percentage of sends marked as spam by Gmail users), authentication pass rates (SPF, DKIM, DMARC), delivery errors (bounces, 5xx codes), and IPv6 reputation. This is the single best signal for Gmail specifically — all other deliverability metrics are inferred. Check weekly; sudden drops in reputation or spikes in spam rate are the earliest warning of a developing inbox-placement problem. Setting up requires DNS TXT verification of the domain and a few days to accumulate sufficient volume for Gmail to display readings.