Spam protection
A clean list is a deliverable list
Bad addresses are the fastest way to wreck your sender reputation. SMASHSEND filters bots, typos and duplicates at signup, before they ever reach your list.
Protection at every step
Bot filtering
A captcha plus a hidden honeypot field stops automated signups without adding friction for real people.
Typo detection
Common domain typos like gmial.com are caught at signup, so you do not lose a real subscriber to a slip.
Double opt-in
Require a confirmation click before an address counts. The single most effective way to keep a list clean.
Duplicate prevention
The same address cannot join twice, which keeps your counts honest and your referral program fair.
Origin allowlisting
Restrict which domains may submit to your form, so nobody can post to it from somewhere else.
Submission limits
Cap how many entries a form accepts, and close it automatically when you hit the number.
Frequently asked questions
Why does spam protection matter for deliverability?
Mailbox providers judge you on how recipients react. Bot addresses and typos produce hard bounces and zero engagement, which pushes your reputation down and your future email into spam.
Does double opt-in cost me subscribers?
It lowers your raw signup count and raises the quality of what remains. Because unconfirmed addresses are the ones that bounce and never open, most senders see better inbox placement overall.
Can I check addresses I already have?
Yes. Use the free email spell checker to catch typos in an existing list before you import it.
Protect your list from day one
Turn on spam protection when you build your first form. It costs nothing and saves your reputation.
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