What is “historical trust” in email sending?

Historical trust is the accumulated credibility your domain earns through consistent, reliable sending behavior over an extended period. It represents the weight of your track record in the eyes of mailbox providers.

Senders with years of clean authentication, low complaint rates, and healthy engagement have built a reservoir of trust. This buffer protects them when something occasionally goes wrong, like an unexpectedly high bounce rate from a single campaign.

New senders have no historical trust. Every early action is scrutinized more heavily because providers have no baseline to compare against. This is why IP warming and gradual volume increases matter so much for new domains.

Historical trust is like the captain's logbook filled with successful voyages. When a storm hits, the harbor master gives more leeway to a captain with decades of clean records than to one on their first crossing.