Private email infrastructure & deliverability engineering
northboundmail.net
NorthboundMail Systems
Est. 2011 — SMTP infrastructure & deliverability
Infrastructure

Bounce Processing

Structured bounce classification, suppression list management, and remediation workflows. Bounces are the single most under-rated deliverability signal — treating them well protects your reputation before it degrades.

Overview

Every message that fails to deliver produces a bounce. The nature of that bounce — hard, soft, blocked, throttled, deferred — is a diagnostic signal. Northbound's bounce processing pipeline classifies every DSN, categorises it against provider-specific patterns, and routes it to the correct downstream action.

Hard bounces feed into the suppression list. Soft and deferred bounces feed into rate-control decisions. Blocklist and reputation-driven bounces trigger alerts to engineering. Nothing is discarded and nothing is silently retried into oblivion.

Benefits

  • Every DSN classified, tagged and stored
  • Provider-specific categorisation (Gmail, Microsoft, Yahoo, Apple, corporate)
  • Suppression enforced across all streams by default
  • Retry policy defined per bounce class, not per message

Technical specifications

ClassificationRFC 3463 status codes + provider-specific patterns
SuppressionEnforced at the MTA level, per-account or global
RetentionBounce events retained for the life of the account

Use cases

  • — Senders whose complaint rate is masked by unclassified soft bounces
  • — Programs migrating between platforms and needing to seed suppression

Questions

Do you export the suppression list?
Yes. Suppression is the client's data. Full exports in CSV or JSON are available on demand.

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