ZapBounce and Postmark
Postmark is strict about what it will carry: transactional mail only, with bounce rates monitored and accounts reviewed. That strictness is why its delivery is good.
It also means a bounce rate problem here is an account standing problem rather than a deliverability metric.
Postmark reviews accounts, and a bounce rate is a signal
Postmark separates transactional and broadcast streams deliberately and will ask questions about a transactional stream producing bounces, because a transactional recipient should be someone who just gave you their address.
A high bounce rate on a transactional stream suggests either signup data nobody validates or marketing mail in the wrong stream. Both get attention.
Postmark also maintains suppressions, and reactivation requires the API or the interface, so an unfairly suppressed customer stays silent until someone acts.
How the data moves
Verify at signup, which is the transactional source
Transactional recipients are people who just typed their address. That is where the typo is, and where it is cheapest to catch.
Keep the streams separated as Postmark intends
Broadcast in the broadcast stream. Mixing them is what draws the account review.
Handle the bounce webhook
Postmark's webhook tells you immediately, which lets you contact the customer another way while the context is fresh.
Reactivate suppressions selectively
Where verification says an address is valid and the suppression came from a soft bounce, reactivation is reasonable.
Setting it up
- Add verification to the signup path before the first transactional send.
- Confirm broadcast mail is in the broadcast stream, not the transactional one.
- Register the bounce webhook and act on it immediately rather than daily.
- Export suppressions and verify them as a batch.
- Reactivate addresses that verify as valid and were suppressed on a soft bounce.
- Watch the transactional bounce rate as an account-health number rather than a marketing one.
Postmark: common questions
Why is Postmark strict about bounce rates?
Because transactional recipients just gave you their address. A high bounce rate suggests either unvalidated signups or marketing mail in the wrong stream.
Can I reactivate a suppressed address?
Through the API, yes. Do it where verification says the address is valid and the suppression came from a temporary failure.
Where should verification run?
At signup. That is the source of every transactional recipient and the only cheap moment to catch a typo.
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