Bounce Processing#

A bounce is a message that a remote server refused to accept. Novaza Pulse processes bounces automatically so your sender reputation stays healthy and your list stays clean. You do not need to write any code to benefit from bounce processing — it is on by default for every campaign.

Hard vs. Soft Bounces#

Hard bounces are permanent failures. The address will never deliver:

mailbox does not exist
domain does not exist
message rejected by policy

Hard-bounced addresses are disabled immediately and will not receive any future sends.

Soft bounces are temporary failures. The address may deliver later:

mailbox full
server temporarily unavailable
message too large

Soft-bounced addresses are retried on a backoff schedule. If soft bounces persist for 5 consecutive sends, the address is treated as hard-bounced and disabled.

How It Works#

Pulse sends the campaign through the SMTP pipeline
Remote servers return SMTP responses or send DSN (Delivery Status Notification) messages back
Pulse parses the SMTP codes and DSNs, classifies the bounce, and updates the subscriber record
The bounce is recorded in the campaign’s activity log

Bounce Reports#

Every campaign report shows:

Delivered, Bounced (hard / soft), Blocked by spam filter
The list of bounced addresses with their SMTP reason
A trend line of your bounce rate over time

Consistently high bounce rates (> 2%) are a warning sign that your list needs cleaning. Pulse will throttle sends automatically if bounce rates exceed safe thresholds, to protect your sending reputation.

Feedback Loops#

For the major mailbox providers (Gmail, Outlook, Yahoo, Apple), Pulse subscribes to feedback loops so that spam complaints from recipients are also captured. Complainants are unsubscribed immediately.

Re-enabling an Address#

An address that was auto-disabled can be re-enabled manually from the subscriber detail page. Use this only if you know the bounce cause has been resolved — repeatedly re-sending to bad addresses damages your sending reputation for everyone.

Webhook#

You can subscribe to bounce.hard, bounce.soft, and complaint events through webhooks to keep your own systems in sync. See the Transactional API for details.