Mailbox providers decide whether to trust a sender by two numbers: how much of its mail goes to addresses that do not exist, and how much recipients mark as spam. Your project's email page now shows both, for the mail you sent over the last seven days, next to the thresholds your project is held to.
Warned before anything stops
When either rate reaches its warning threshold, the person who pays for the project gets an email and a notification saying which rate is high and how far it is from the limit. Sending carries on as normal.
If a rate keeps climbing and reaches its suspension threshold, email sending
for the project is suspended. SMTP refuses new messages with a permanent
550 error, and sending through the API returns
403 EMAIL_SENDING_SUSPENDED. A suspension does not lift on its own:
open a support ticket, tell us what was sent and
what you have changed, and we will review it.
Rates are only judged once a project has sent enough mail for them to mean something, so a single complaint against a handful of messages never counts against you. An address that has bounced is never sent to again, and those blocked sends are not counted either.
Read it from the API
The same figures are available from
GET /v1/projects/:projectId/email/reputation, with the email:read scope.
See Sending Reputation for how the rates are measured and how to keep them low.