Concept explainersUpdated 5/13/2026
Why email verification matters (and what happens when you skip it)
Sending to unverified emails is the fastest way to destroy your sender reputation. Every bounce damages your domain's standing with Gmail/Outlook/etc., dropping inbox placement for ALL future sends — not just the current campaign.
The bounce-rate threshold
Gmail flags senders at >5% bounce rate. Above 10% you're effectively in spam folders for weeks. Above 20% your domain is burned.
Sender reputation recovery
Takes 30-90 days of clean sending from a fresh domain to recover. Most teams don't recover the original domain — they buy a new one and start the warmup process.
Catch-all trap
Catch-all servers accept every email, so verification falsely passes. Real mailbox doesn't exist → still bounces. Always flag + filter catch-alls separately.
Tools mentioned in this guide
Keep reading
Ready to try Kavex?
1,000 free credits on signup. No credit card.
Get started