Customers
Register existing customers for suppression
Register one or more existing-customer addresses so they are suppressed
from future mailings. Accepts a single { address, notes? } or a batch
{ addresses: [...] }. Upserted on the normalized address per org.
A batch is capped at 1000 addresses — more is a 422. The endpoint is
rate-limited to 60 requests / minute / org in its own bucket
(429 with Retry-After: 60).
POST
Authorizations
Organization-scoped Mailr API key. Header: Authorization: Bearer ak_….