Stripe Radar vs Custom Fraud Prevention: When You Need Both

Stripe Radar is a machine learning-based fraud detection system included with every Stripe account. It evaluates transactions using data from millions of businesses on the Stripe network, blocking stolen cards and known bad actors automatically.

For many businesses, Radar handles the basics well. But it has significant blind spots that leave you exposed to the fraud patterns that actually cause the most damage.

What Stripe Radar Does Well

Radar excels at payment-level fraud detection:

• Stolen card detection — Identifies cards reported as stolen or compromised across the Stripe network
• Pattern recognition — ML models trained on billions of transactions identify anomalous payment behavior
• 3D Secure triggering — Automatically routes risky transactions through additional authentication
• Built-in rules — Block payments from specific countries, card types, or risk levels
• Network intelligence — Benefits from seeing fraud patterns across all Stripe merchants

If your primary fraud problem is stolen credit cards being used on your checkout page, Radar likely handles it adequately.

Where Stripe Radar Falls Short

Radar only activates when a payment is processed. Everything that happens before that — signup, account creation, free tier usage — is invisible to it.

Blind Spot 1: Disposable Emails

Radar does not check whether an email address is disposable. A user can sign up with throwaway@mailinator.com, abuse your free tier for weeks, and Radar never flags it because no payment was attempted.

Blind Spot 2: Pre-Signup Risk

The most effective fraud prevention happens before account creation. By the time a fraudster reaches checkout, they've already consumed resources, polluted your user data, and may have exploited your free tier.

Blind Spot 3: Account-Level Fraud

Multi-account fraud (one person creating many accounts to exploit promotions, free tiers, or referral programs) is invisible to Radar. Each account looks like a normal user until they attempt payment.

Blind Spot 4: Friendly Fraud Signals

Radar catches obviously stolen cards but struggles with friendly fraud — legitimate customers who dispute charges after receiving the product. The signals that predict friendly fraud (mismatched geolocation, recent email creation, behavioral patterns) happen before the payment.

The Layered Approach

The most effective fraud prevention uses both Radar and a pre-transaction service like Fidro, each covering different parts of the customer lifecycle:

Layer 1: At Signup (Fidro)

curl -X POST https://api.fidro.io/v1/validate/email \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"email": "user@example.com"}'

• Block disposable emails
• Check domain age and DNS validity
• Flag high-risk email patterns
• Store validation data for later use in disputes

Layer 2: During Usage (Your Application)

• Monitor for multi-account patterns
• Track usage anomalies
• Flag accounts that match free-tier abuse patterns

Layer 3: At Checkout (Fidro + Stripe Radar)

curl -X POST https://api.fidro.io/v1/validate/email \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"email": "user@example.com", "ip": "203.0.113.42"}'

• Fidro: IP geolocation, VPN/proxy detection, combined risk score
• Radar: Card-level fraud detection, 3D Secure, network intelligence

Layer 4: Post-Transaction (Stripe Radar)

• Automated dispute handling
• Evidence submission (using Fidro's stored validation data)

Cost Comparison

For a business processing 10,000 transactions per month, Radar for Fraud Teams costs $700/month. Fidro Starter costs $29/month for 5,000 validations and covers the pre-transaction signals that Radar misses.

When Radar Alone Is Sufficient

Stripe Radar by itself may be enough if:

• You don't have a free tier or trial
• Your product requires payment at signup
• You don't experience account-level fraud
• Your chargeback rate is below 0.3%
• You sell physical goods with delivery tracking

When You Need Both

Add pre-transaction fraud detection if:

• You have a free tier that gets abused
• You experience chargebacks from seemingly legitimate customers
• Your chargeback rate is above 0.5%
• You see patterns of multi-account creation
• You sell digital goods or SaaS subscriptions

Getting Started

1. Keep Stripe Radar active — it's free and handles payment-level fraud well
2. Add Fidro for email validation at signup — the free plan gives you 1,000 checks/month
3. Store Fidro validation data on customer records for dispute evidence
4. Review your fraud metrics after 30 days and adjust thresholds