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Documentation Index

Fetch the complete documentation index at: https://docs.openmail.sh/llms.txt

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When an email bounces, a recipient marks your email as spam, or someone unsubscribes, we automatically add them to your suppression list. Subsequent send attempts to that address are rejected.

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Suppression types

TypeTriggerWhat it means
bounceHard bounce from recipient serverAddress is invalid or doesn’t exist
complaintRecipient clicked “Report spam”Recipient doesn’t want email from you
unsubRecipient unsubscribedRecipient opted out

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What happens when you send to a suppressed address

The send request returns 422 with a typed error: 
{
  "error": "recipient_suppressed",
  "type": "complaint"
}
Your agent should handle this gracefully - for example, by noting that the contact is unreachable and trying an alternative communication channel. Suppressions are one part of maintaining good deliverability. For the full picture — warm-up strategy, inbox distribution, and content best practices — see Email deliverability.