Stop SaaS Signup Fraud & Fake Accounts
Protect your SaaS platform from free-trial abusers and fraudulent signups by blocking temporary emails at the registration edge.
Protect Free Trials
Stop abusers from endlessly creating new accounts with disposable emails to exploit your freemium tier.
Clean Database
Keep your CRM and user database pristine. Real users mean accurate analytics and higher retention metrics. Protect your platform by blocking temporary email accounts before they register.
Zero Friction
Sub-50ms API response times ensure that legitimate users experience zero latency during the onboarding process.
Experience the Speed
Try MailCheck API right now. We validate syntax, MX records, and check against our global disposable database in milliseconds.
curl -X POST "https://fadsync-email-validation.p.rapidapi.com/v1/check" \
-H "Content-Type: application/json" \
-H "X-RapidAPI-Key: YOUR_API_KEY" \
-H "X-RapidAPI-Host: fadsync-email-validation.p.rapidapi.com" \
-d '{"email": "user@example.com"}'The True Cost of SaaS Signup Fraud
Fake accounts and disposable email signups are a silent killer for modern SaaS startups. When malicious users or bots leverage temporary email generators (like TempMail or GuerrillaMail) to bypass your authentication flows, they immediately degrade your platform’s health. These users farm free-trial credits, scrape proprietary data, and consume valuable server resources without ever intending to convert into paying customers.
Beyond server costs, fake accounts severely distort your core business metrics. When your user acquisition data is polluted with hundreds of disposable email signups, calculating accurate Customer Acquisition Cost (CAC) and Lifetime Value (LTV) becomes impossible. Blocking these accounts at the registration edge is fundamentally critical for maintaining a clean, accurate CRM.
How to Block Disposable Emails in Modern Stacks (Clerk, Next.js)
Many modern SaaS applications are built on stacks utilizing Next.js, Clerk Auth, or Supabase. Integrating a real-time defense layer requires an API that is fast enough to execute within the synchronous bounds of an authentication webhook or Edge middleware. If you want to seamlessly block disposable emails clerk nextjs or Auth0 environments, your validation API must respond in under 50ms.
MailCheck API is designed specifically for this use case. By maintaining a live 40M+ disposable domain blocklist at the Cloudflare edge, it intercepts malicious signups before they are persisted to your database. Unlike legacy tools that require batch processing, MailCheck instantly returns a clear ALLOW or BLOCK recommendation, empowering your application to gracefully reject the registration attempt instantly.
Preventing Free-Trial and Stripe Abuse
For SaaS platforms offering a free tier or a 14-day trial without a credit card, the barrier to entry is intentionally low. Fraudsters exploit this by cycling through newly minted burner domains to perpetually access premium features for free. This not only robs you of revenue but can also lead to Stripe disputes or infrastructure abuse if your platform sends outbound emails or SMS messages.
Implementing the MailCheck API acts as a zero-day firewall against this abuse. By verifying that every new user possesses a legitimate, permanent email address (with a valid MX record and no known threat association), you drastically reduce the surface area for platform abuse. This ensures that your infrastructure costs are spent serving actual potential buyers rather than bots.
Frequently Asked Questions
Everything you need to know about our stop saas signup fraud & fake accounts solution.
Ready to integrate?
Join the engineering teams already protecting their platforms with MailCheck API.