Mailbloc
Signup fraud detection API - Free
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February 6, 2026
SaaS was flooded with fake signups. Built an API to stop it. It works.
When I launched InputBloc it immediately got hammered with fake users — everyday.
Needed to filter them at signup, not after. So I built MailBloc: a simple API that scores emails and IPs to block fraud before it hits your database.
What MailBloc does:
Email & IP risk scoring
Catches disposable emails, VPNs, Tor network, datacenters, known fraudsters
Stops fake signups cold
Also helps reduce Stripe chargebacks from abusive users
Simple API, generous free tier, you might never pay me a $
I've been running it on InputBloc for months. Spam dropped to zero so far.
Try it: https://mailbloc.com
My question: Are you dealing with fake signups or fraudulent users? What are you using to filter them right now?
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