Referral Fraud Detection
Stop fake referrals
without blocking real ones
Waitlister uses device fingerprinting, IP analysis, email normalization, velocity checks, and disposable email blocking to catch fake referrals — silently, without disrupting legitimate signups. Configurable from off to strict in one click.
6,500+ founders protect their leaderboards with Waitlister






























One bad actor can wreck
your entire leaderboard
Referral programs work — until someone figures out they can game the system. Here's what happens when there's no fraud detection.
Fake signups flood the list
One person creates 50 throwaway emails — mailinator, tempmail, plus-addressed Gmail variants — and "refers" themselves to the top of the leaderboard.
Legitimate referrers give up
Real subscribers who shared your waitlist see a fraud account at #1 with 200 "referrals." They stop sharing. Your viral loop dies.
Your data becomes useless
You can't tell real signups from fake ones. Your subscriber count is inflated. Your email deliverability tanks because half the list is garbage addresses.
Multi-signal scoring that catches fraud
without blocking real signups
Waitlister doesn't just check IP addresses. It combines multiple fraud signals into a score. If the score exceeds your threshold, the referral credit is silently withheld — the signup still goes through, but the referrer doesn't get rewarded.
Device fingerprinting
Uses FingerprintJS to generate a stable visitor ID from browser properties — canvas, WebGL, fonts, screen dimensions. Survives incognito mode and most VPN switches. If the same device signs up twice with the same referral code, it's flagged.
IP analysis
Checks for exact IP matches and /24 subnet clustering within a 30-day window. Catches people cycling through VPN servers on the same provider — the subnet pattern gives them away even when the exact IP changes.
Email normalization
Understands Gmail tricks: [email protected], [email protected], and [email protected] are all the same person. Strips dots, plus-addressing, and googlemail.com aliases before comparing.
Velocity detection
Flags unnatural signup speed — 5+ referrals in an hour or 20+ in a day from the same referral code. Real viral sharing doesn't happen in machine-gun bursts.
Disposable email blocking
Blocks 140+ known burner email domains — mailinator, tempmail, guerrillamail, yopmail, and more. These addresses exist for minutes. Nobody uses them to sign up for a waitlist they actually care about.
Email prefix similarity
Detects patterns like john.doe42@, john.doe43@, john.doe44@ — sequential or near-identical prefixes from the same referral code. A common bot pattern that looks unique per-email but isn't.
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Start building your waitlist with Waitlister and get the most out of your pre-launch campaign
Before choosing Waitlister, I compared several alternatives. Honestly, Waitlister stands far ahead. The product is more intuitive, faster to set up, and clearly built with real attention to detail.
Silent fraud detection
that never blocks real signups
- —Sign up normally, get a thank-you page, receive a welcome email
- —Referrer gets full credit and points
- —Webhooks fire, position is assigned, everything works
- —Signup still goes through — the person joins the waitlist normally
- —Referral credit is silently withheld — the referrer gets no points
- —Fraud signals are logged with scores and reasons for your review
- —Neither side is notified — no "you've been flagged" messages
Four protection levels
Choose how aggressively Waitlister flags fraud. Change it anytime in Settings — takes effect immediately.
No fraud checks. All referrals credited. Useful for testing your referral flow with your own emails.
Blocks only obvious fraud: exact self-referrals and normalized email duplicates. Low risk of false positives.
Full detection: fingerprints, IP matching, velocity, disposable emails, prefix similarity. Recommended for most waitlists.
Lower thresholds. May flag legitimate referrals from shared networks (offices, universities, coffee shops). Use for high-stakes campaigns.
Works via API too
If you're adding subscribers through the API, fraud detection is skipped by default (since the IP Waitlister sees is your server's). Forward the end user's IP and/or fingerprint to enable full detection.
{
"email": "[email protected]",
"metadata": {
"referred_by": "happy-star-4f3d",
"client_ip": "203.0.113.42",
"fingerprint": "abc123def456"
}
} When client_ip or fingerprint is provided, the full fraud pipeline runs. API docs →
Referral fraud detection — common questions
Enable fraud detection in Settings → Referral → Fraud protection. The 'Balanced' level (default) catches most fraud: device fingerprinting blocks same-device signups across browsers and incognito tabs, email normalization catches Gmail dot tricks and plus-addressing, and the disposable email blacklist blocks 140+ temp email services. The key: fraud detection is silent. Fake signups still go through (so the fraudster doesn't know they've been caught), but the referral credit is withheld. The referrer doesn't get points.
First, set fraud protection to 'Strict' to stop new fake referrals immediately. Then review your subscriber list — signups from known disposable domains and those with withheld referral credits are visible in your dashboard. For existing damage: you can manually adjust points via the API, or remove fraudulent subscribers entirely. Going forward, the multi-signal detection (fingerprinting + IP + email normalization + velocity) makes it very difficult for a single person to accumulate fake referrals without being caught.
On 'Balanced' (default), unlikely. Same-IP referrals score 40 points against a 50-point threshold, so they'll only be flagged if combined with another signal (like a fingerprint match or suspicious email pattern). People on the same WiFi network but using different devices with different emails will almost always pass. On 'Strict', same-IP alone is enough to trigger. Use Strict only for high-stakes campaigns where fraud risk outweighs the risk of blocking a few legitimate shared-network referrals.
Yes — that's why it's effective. FingerprintJS generates a visitor ID from browser properties (canvas rendering, WebGL, installed fonts, screen dimensions) that remain consistent across normal and incognito sessions on the same device. If someone opens an incognito tab to fake a referral, the fingerprint still matches their regular session. It's not perfect — some browsers with aggressive anti-fingerprinting (Tor, Brave with strict settings) can evade it. But combined with IP analysis and email normalization, even those cases are usually caught by another signal.
Yes. In your fraud detection settings, you can add up to 5 whitelisted emails that bypass all fraud checks. This is useful when testing your referral flow with your own email addresses — you won't accidentally flag yourself as a fraudster. Alternatively, set the protection level to 'Off' temporarily during testing, then switch back to 'Balanced' before your waitlist goes live.
Very few. Most waitlist tools (LaunchList, Prefinery) have no fraud detection at all. Waitlist.com has basic checks. Viral Loops flags high-risk participants but users report that bots still get through. Waitlister is the only waitlist tool with device-fingerprint-based fraud detection, email normalization (Gmail dot tricks, plus-addressing), velocity scoring, disposable email blocking, and configurable protection levels — all included from the Launch plan at $15/mo. GrowSurf has comprehensive fraud detection, but it's referral software for established products ($125+/mo), not a waitlist tool.
No. Fraud detection is included on the Launch plan ($15/mo) and above — the same plan that includes referrals. There's no separate add-on or per-check pricing.
Yes. This is a complementary strategy. In your thank-you page editor, turn off 'Show position' while keeping the leaderboard and referral section visible. Subscribers see the leaderboard ranked by points but never see their exact position number — removing the incentive to game from #47 to #12. Combine this with fraud detection for a belt-and-suspenders approach. Read more about hiding positions in the position inflation docs.
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