A workspace SaaS kept transactional invite emails out of spam at viral-loop scale
User invites were the dominant growth loop. Verifying invite addresses before sending kept transactional deliverability strong even at spike volumes.
Persona: A collaborative-workspace SaaS
What was breaking
The product's viral loop ran on user-initiated invitations. Each invite went through the platform's transactional sending infrastructure. Typos in invite addresses returned hard bounces; bounces correlated with the same sender domain that delivered password resets and security notifications. A transactional deliverability problem would have been catastrophic.
How emailzeno fit the workflow
The invite-send pipeline was wired through emailzeno verification first. Undeliverable addresses returned a sender-side error so the inviter could correct the typo immediately. Deliverable addresses passed through to the existing transactional sender. The hygiene gate cost milliseconds; the bounce share dropped immediately.
What changed
Transactional sender-domain reputation strengthened. Password-reset and security-notification deliverability remained rock-solid through viral-growth periods that previously caused inbox-placement wobbles. The marketing email program inherited the cleaner reputation.
“A password-reset that lands in spam is a churned customer. Verification was the lowest-cost insurance we could buy.”
The emailzeno building blocks
Inline at the invite form
Catches the typo where the sender entered it, so they can fix it before the loop fires. Better UX than a silent bounce later.
Transactional-grade latency
Sub-300 ms p95. Acceptable inside the request path for transactional emails where users expect immediate confirmation.
Separate credit pools
Track transactional vs marketing usage independently. Different SLAs, different growth profiles, one bill.
Questions teams ask before adopting
Run the same play.
First 300 verifications free. 99.95% API uptime SLA.